Novell LINUX ENTERPRISE SERVER 10 SP3 - ARCHITECTURE-SPECIFIC Page 7 Administration Manual Download

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Contents

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6.1.6

Interoperability Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

6.1.7

Guidelines for Component Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

6.1.8

RAID 5 Algorithms for Distributing Stripes and Parity . . . . . . . . . . . . . . . . . . . . . . . . 82

6.1.9

Multi-Disk Plug-In for EVMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

6.1.10

Device Mapper Plug-In for EVMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

6.2

Creating and Configuring a Software RAID . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

6.3

Expanding a RAID . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
6.3.1

Adding Mirrors to a RAID 1 Device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

6.3.2

Adding Segments to a RAID 4 or 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

6.4

Adding or Removing a Spare Disk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
6.4.1

Do You Need a Spare Disk? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

6.4.2

Adding a Spare Disk When You Create the RAID . . . . . . . . . . . . . . . . . . . . . . . . . . 89

6.4.3

Adding a Spare Disk to an Existing RAID . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

6.4.4

Removing a Spare Disk from a RAID . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

6.5

Managing Disk Failure and RAID Recovery. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
6.5.1

Understanding the Disk Failure and RAID Recovery. . . . . . . . . . . . . . . . . . . . . . . . . 89

6.5.2

Identifying the Failed Drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

6.5.3

Replacing a Failed Device with a Spare . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

6.5.4

Removing the Failed Disk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

6.6

Monitoring Status for a RAID . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
6.6.1

Monitoring Status with EVMSGUI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

6.6.2

Monitoring Status with /proc/mdstat. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

6.6.3

Monitoring Status with mdadm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

6.6.4

Monitoring a Remirror or Reconstruction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

6.6.5

Configuring mdadm to Send an E-Mail Alert for RAID Events. . . . . . . . . . . . . . . . . . 95

6.7

Deleting a Software RAID and Its Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

7 Managing Software RAIDs 6 and 10 with mdadm

7.1

Creating a RAID 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
7.1.1

Understanding RAID 6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99

7.1.2

Creating a RAID 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

7.2

Creating Nested RAID 10 Devices with mdadm. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
7.2.1

Understanding Nested RAID Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

7.2.2

Creating Nested RAID 10 (1+0) with mdadm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

7.2.3

Creating Nested RAID 10 (0+1) with mdadm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102

7.3

Creating a Complex RAID 10 with mdadm. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
7.3.1

Understanding the mdadm RAID10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

7.3.2

Creating a RAID10 with mdadm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

7.4

Creating a Degraded RAID Array. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

8 Resizing Software RAID Arrays with mdadm

109

8.1

Understanding the Resizing Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
8.1.1

Guidelines for Resizing a Software RAID . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

8.1.2

Overview of Tasks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110

8.2

Increasing the Size of a Software RAID. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
8.2.1

Increasing the Size of Component Partitions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110

8.2.2

Increasing the Size of the RAID Array . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111

8.2.3

Increasing the Size of the File System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112

8.3

Decreasing the Size of a Software RAID . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114
8.3.1

Decreasing the Size of the File System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114

8.3.2

Decreasing the Size of Component Partitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116

8.3.3

Decreasing the Size of the RAID Array . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117

Summary of Contents for LINUX ENTERPRISE SERVER 10 SP3 - ARCHITECTURE-SPECIFIC

Page 1: ...Novell www novell com novdocx en 7 January 2010 AUTHORIZED DOCUMENTATION SLES 10 SP3 Storage Administration Guide SUSE Linux Enterprise Server 10 SP3 February 23 2010 Storage Administration Guide...

Page 2: ...or re export to entities on the current U S export exclusion lists or to any embargoed or terrorist countries as specified in the U S export laws You agree to not use deliverables for prohibited nucl...

Page 3: ...this document is copied distributed and or modified from the following document under the terms specified in the document s license EVMS User Guide January 18 2005 Copyright 2005 IBM License Informat...

Page 4: ...4 SLES 10 SP3 Storage Administration Guide novdocx en 7 January 2010...

Page 5: ...Restart the Server 26 2 2 7 Verify that EVMS Manages the Boot Swap and Root Partitions 26 2 3 Configuring LVM Devices to Use EVMS 27 2 4 Using EVMS with iSCSI Volumes 27 2 5 Using the ELILO Loader Fi...

Page 6: ...oning Multipathed Devices 54 5 4 3 Configuring the Server for Multipathing 55 5 4 4 Adding multipathd to the Boot Sequence 55 5 4 5 Creating and Configuring the etc multipath conf File 56 5 5 Enabling...

Page 7: ...6 4 Monitoring a Remirror or Reconstruction 95 6 6 5 Configuring mdadm to Send an E Mail Alert for RAID Events 95 6 7 Deleting a Software RAID and Its Data 97 7 Managing Software RAIDs 6 and 10 with...

Page 8: ...MS 125 10 3 Volumes on EVMS Devices Do Not Appear After Reboot 125 10 4 Volumes on EVMS Devices Do Not Appear When Using iSCSI 126 10 5 Device Nodes Are Not Automatically Re Created on Restart 126 A D...

Page 9: ...ence This guide is intended for system administrators Feedback We want to hear your comments and suggestions about this manual and the other documentation included with this product Please use the Use...

Page 10: ...anuary 2010 Documentation Conventions In Novell documentation a greater than symbol is used to separate actions within a step and items in a cross reference path A trademark symbol TM etc denotes a No...

Page 11: ...er A plug in framework for flexible extensibility and customization Plug ins to extend functionality for new or evolving storage managers Support for foreign partition formats Cluster aware 1 2 Plug I...

Page 12: ...wiki novell com index php File_System_Primer describes the variety of file systems available on Linux and which ones are the best to use for which workloads and data 1 4 Terminology EVMS uses the foll...

Page 13: ...er Storage Container A storage container managed by the Cluster Resource Manager It is accessible to all nodes of a cluster An administrator can configure the storage objects in the cluster container...

Page 14: ...ects the storage objects actually present on a system and creates an appropriate device node for each one such as those shown in the following table Table 1 3 Device Node Location Storage Object Stand...

Page 15: ...l on page 15 Section 2 1 2 During the Server Install on page 17 Section 2 1 3 After the Server Install on page 20 2 1 1 Before the Install System Device on page 15 Device Size Limits on page 16 Data L...

Page 16: ...n and Administration Guide http www novell com documentation sles10 Data Loss Considerations for the System Device This install requires that you delete the default partitioning settings created by th...

Page 17: ...tioner dialog box 2d Select Expert Delete Partition Table and Disk Label then click Yes twice to continue through the Warning advisories This deletes the recommended partitions and the partition table...

Page 18: ...e processes run out of RAM space Swap is not required for systems with more than 1 GB of RAM You must have at least 1 GB of virtual memory RAM plus swap during the install but if the swap is more than...

Page 19: ...cify a volume name such as sys_lx 7d In the Size field click Max to set the size of the system volume as the remaining space available in the lvm system partition 7e Specify the mount point as root vo...

Page 20: ...steps you disable boot lvm and boot md then enable boot evms In effect this forces EVMS to scan all the partitions at boot time including the boot partition and it activates boot under the dev evms d...

Page 21: ...Disable the boot lvm and boot md Services on page 21 Disable the boot lvm and boot md Services Disable the boot lvm and boot md services so they do not run at boot time runlevel B EVMS now handles the...

Page 22: ...or root partitions you can optionally configure the device for EVMS at any time after the install If you do not configure the device to use EVMS you must manage the device and all of its volumes with...

Page 23: ...nterprise 10 the dev directory is on tmpfs and the device nodes are automatically re created on boot It is no longer necessary to modify the etc init d boot evms script to delete the device nodes on s...

Page 24: ...Section 2 2 4 Edit the Boot Loader File on page 24 2 2 4 Edit the Boot Loader File When you boot the system the kernel reads the boot loader file for information about your system For Grub this is th...

Page 25: ...c lilo conf file 3 Locate the line that contains the root parameter For example if your root file system uses device sda1 look for a line similar to this kernel sd0 0 vmlinuz root dev sda1 vga 0x31a s...

Page 26: ...Section 2 2 6 Restart the Server on page 26 2 2 6 Restart the Server 1 Restart the server to apply the post install configuration settings When your system restarts the kernel loads the init ramdisk w...

Page 27: ...pts as follows The command evms_activate must be run from your boot scripts in order to activate your volumes so they can be mounted If you run software RAID boot md or LVM boot lvm boot files in your...

Page 28: ...es not start during the system boot you must activate it manually 1 Open a terminal console then log in as the root user or equivalent 2 At the terminal console prompt enter evms_activate 2 7 Starting...

Page 29: ...rt 3 Start the server When the server comes back up evmsgui is not automatically loaded on restart evms Starts the EVMS commandline interpreter CLI interface For information about command options see...

Page 30: ...30 SLES 10 SP3 Storage Administration Guide novdocx en 7 January 2010...

Page 31: ...regardless of their order of recognition or the connection used for the device The udev tools examine every appropriate block device that the kernel creates to apply naming rules based on certain bus...

Page 32: ...n you cannot change the label name when the partition is mounted You can use the UUID as criterion for assembling and activating software RAID devices When a RAID is created the md driver generates a...

Page 33: ...fy Fstab Options Edit the etc fstab file to modify the system device from the location to the UUID For example if the root volume has a device path of dev sda1 and its UUID is e014e482 1c2d 4d09 84ec...

Page 34: ...sda1 reiserfs acl user_xattr 1 1 to UUID e014e482 1c2d 4d09 84ec 61b3aefde77a reiserfs acl user_xattr 1 1 IMPORTANT Make sure to make a backup copy of the boot efi SuSE elilo conf file before you beg...

Page 35: ...Segment Managers The most commonly used segment manager is the DOS Segment Manager The following table describes the segment managers available in EVMS Table 4 1 EVMS Segment Managers Segment Manager...

Page 36: ...e so the limit also applies to the md plug in for EVMS Software RAID devices you create with EVMS can be larger than 2 TB of course because the md driver plug in manages the disks underneath that stor...

Page 37: ...tibility volume For example a new disk sdb would show up as dev evms sdb Delete it from the Volumes list to force the disk to show up in Available Objects then create segments as desired 4 2 3 Adding...

Page 38: ...anager for the device you want to manage then click Next DOS Segment Manager the most common choice GPT Segment Manager for IA 64 platforms Cluster Segment Manager available only if it is a viable opt...

Page 39: ...volume on the server By default this field is empty Mount read only Select the check box to enable this option It is deselected disabled by default If this option is enabled files and directories can...

Page 40: ...ata to the file system then enters the metadata in the journal This is the default Journal Writes data twice once to the journal then to the file system Writeback Writes data to the file system and wr...

Page 41: ...configure multipathing for the devices before creating software RAIDs or file system volumes on the devices For information see Chapter 5 Managing Multipath I O for Devices on page 43 If you want to c...

Page 42: ...42 SLES 10 SP3 Storage Administration Guide novdocx en 7 January 2010...

Page 43: ...Devices without Rebooting on page 71 Section 5 12 Viewing Multipath I O Status on page 72 Section 5 13 Managing I O in Error Situations on page 73 Section 5 14 Resolving Stalled I O on page 74 Section...

Page 44: ...Supported Storage Arrays for Multipathing on page 47 5 2 1 Guidelines for Multipathing Use the guidelines in this section when planning your multipath I O solution Prerequisites on page 44 Vendor Pro...

Page 45: ...ent running underneath High Availability Solutions High availability solutions for clustering typically run on top of the multipathing server For example the Distributed Replicated Block Device DRBD h...

Page 46: ...settings Enter mkinitrd f mpath 7 Reboot the server to apply the changes 5 2 4 Using mdadm with Multipath Devices The mdadm tool requires that the devices be accessed by the ID rather than by the dev...

Page 47: ...4T IPF IA64 p Series 32 bit 64 bit z Series 31 bit and 64 bit 5 2 8 Supported Storage Arrays for Multipathing The multipathing drivers and tools in SUSE Linux Enterprise Server 10 support most storage...

Page 48: ...all of the storage arrays that are automatically detected have been tested on SUSE Linux Enterprise Server For information see Tested Storage Arrays for Multipathing Support on page 48 Some storage ar...

Page 49: ...ted storage arrays see Tested Storage Arrays for Multipathing Support on page 48 5 3 Multipath Management Tools The multipathing support in SUSE Linux Enterprise Server 10 is based on the Device Mappe...

Page 50: ...are connected to the wrong storage processor the one with the passive path you might not see the expected LUNs or you might see the LUNs but get errors when trying to access them Table 5 1 Multipath...

Page 51: ...th tools Package For a list of files included in this package see the multipath tools Package Description http www novell com products linuxpackages suselinux multipath tools html 1 Ensure that the mu...

Page 52: ...led by entering the following at a terminal console prompt rpm q mdadm If it is installed the response repeats the package name and provides the version information For example mdadm 2 6 0 11 If it is...

Page 53: ...e of the group policy options that are described in Table 5 3 on page 53 Table 5 3 Group Policy Options for the multipath p Command 5 4 Configuring the System for Multipathing Section 5 4 1 Preparing...

Page 54: ...A driver check the zoning setup of the SAN In particular check whether LUN masking is active and whether the LUNs are correctly assigned to the server If the LUNs are seen by the HBA driver but there...

Page 55: ...gic controller accessed by the driver qla2xxx this entry would look like INITRD_MODULES cciss Because the QLogic driver is not automatically loaded on start up add it here INITRD_MODULES cciss qla23xx...

Page 56: ...rminal console log in as the root user 2 Enter the following command all on one line of course to copy the template cp usr share doc packages multipath tools multipath conf synthetic etc multipath con...

Page 57: ...device node names in the form of dev sdn and dev dm n can change on reboot referring to multipath devices by their ID is preferred The multipath device names in the dev mapper directory reference the...

Page 58: ...ion looks like this blacklist wwid 26353900f02796769 devnode ram raw loop fd md dm sr scd st sda 0 9 devnode hd a z 0 9 devnode cciss c 0 9 d 0 9 You can also blacklist only the partitions from a driv...

Page 59: ...take effect when multipathd is running After you make changes save and close the file then do the following to apply the changes 1 Stop the multipathd service 2 Clear old multipath bindings by enteri...

Page 60: ...6 4 Configuring ALUA on page 65 Section 5 6 5 Reporting Target Path Groups on page 67 5 6 1 Configuring the Path Failover Policies Use the multipath command with the p option to set the path failover...

Page 61: ...iven device its paths with the same priorities belong to the same priority group Table 5 5 Multipath Attributes Multipath Attribute Description Values user_friendly_names Specifies whether to use IDs...

Page 62: ...er Reads the first sector that has direct I O This is useful for DASD devices Logs failure messages in var log messages readsector0 Default in multipath tools version 0 4 7 and earlier Reads the first...

Page 63: ...s generate path priorities when queried by the multipath command The program names must begin with mpath_prio_ and are named by the device type or balancing method used Current prioritizer programs in...

Page 64: ...ng method to use for paths uniform Default All paths have the same round robin weightings priorities Each path s weighting is determined by the path s priority times the rr_min_io setting no_path_retr...

Page 65: ...63 2 0x10000000c95ebeb4 0x200200a0b8122c6e 2 0 0 2 sdd 3600a0b8000122c6d0000000345317524 50 0x10000000c95ebeb4 0x200200a0b8122c6e 2 0 0 3 sde 3600a0b80000fd6320000000245317593 2 0x10000000c95ebeb4 0x2...

Page 66: ...e SCSI device you want to manage The device must be a SCSI device that supports the Report Target Port Groups sg_rtpg 8 command Use one of the following formats for the device node name The full Linux...

Page 67: ...our HBA to disable failover at the HBA level to allow the failure to propogate up to the multipath I O layer as fast as possible where the I O can be redirected to another healthy path To disable the...

Page 68: ...the DM MP service might be starting after the multipath service on reboot which makes multipathing appear not to be available for RAIDs You can use the procedure in this section to get multipathing r...

Page 69: ...Restart the boot md service and the RAID device by entering etc init d boot md start 7 Check the status of the software RAID by entering mdadm detail dev mapper mpath0 The RAID s component devices sho...

Page 70: ...les removing of devices Default Disabled i issueLip Issues a Fibre Channel LIP reset Default Disabled forcerescan Rescans existing devices forceremove Removes and re adds every device DANGEROUS noopts...

Page 71: ...ultipathd mpath4 event checker started Feb 14 01 03 multipathd mpath5 event checker started Feb 14 01 03 multipathd mpath4 remaining active paths 1 Feb 14 01 03 multipathd mpath5 remaining active path...

Page 72: ...y the dev dm 9 path then change the entry before the next time you reboot to LABEL oradata3 12 Create a directory to use as the mount point then mount the device by entering md oradata3 mount oradata3...

Page 73: ...A or the fabric experiences spurious errors it is advisable that DM MP be configured to queue all I O where those errors lead to a loss of all paths and never propagate errors upwards Because this lea...

Page 74: ...for the device This causes all queued I O to fail and propagates the error to the calling application 2 Reactivate queueing by entering the following command at a terminal console prompt dmsetup mess...

Page 75: ...8 Troubleshooting SCSI LUN Scanning Issues Technical Information Document 3955167 http www novell com support search do cmd displayKC docType kc externalId 3955167 sliceId SAL_Public dialogI D 5786870...

Page 76: ...76 SLES 10 SP3 Storage Administration Guide novdocx en 7 January 2010...

Page 77: ...Comparison of RAID Performance on page 79 Section 6 1 4 Comparison of Disk Fault Tolerance on page 79 Section 6 1 5 Configuration Options for RAIDs on page 80 Section 6 1 6 Interoperability Issues on...

Page 78: ...dundancy Any disk failure causes all data in the RAID to be lost 1 Mirrors data by copying blocks of one disk to another and keeping them in continuous synchronization If disks are different sizes the...

Page 79: ...disk fails performance is degraded while the RAID uses the parity to reconstruct data for the replacement disk Provides slightly less data redundancy than mirroring because it uses parity to reconstr...

Page 80: ...t or region to use as the replacement for a failed disk the member device segment or region On failure the spare disk automatically replaces the failed disk then reconstructs the data However if the p...

Page 81: ...I O performance and to achieve disk fault tolerance where supported by the RAID level you use In addition they should be of the same type disks segments or regions Using component devices of differing...

Page 82: ...c 2 This is the default setting and is considered the fastest method for large reads Stripes wrap to follow the parity The parity s position in the striping sequence moves in a round robin fashion fro...

Page 83: ...nterface and in naming of device nodes but implements the storage objects with Device Mapper Linear RAID A linear concatenation of discontinuous areas of free space from the same or multiple storage d...

Page 84: ...ion Create Segment to open the DOS Segment Manager 4b Select the free space segment you want to use 4c Specify the amount of space to use for the segment 4d Specify the segment options then click Crea...

Page 85: ...ionally specify a device to use as the spare disk for the RAID The default is none For RAIDs 0 4 or 5 specify the chunk stripe size in KB The default is 32 KB For RAIDs 4 5 specify RAID 4 or RAID 5 de...

Page 86: ...d ASCII characters and naming conventions Spaces are allowed 6d Click Done 7 Create a file system on the RAID device you created 7a Select Action File System Make to view a list of file system modules...

Page 87: ...g Segments to a RAID 4 or 5 on page 88 6 3 1 Adding Mirrors to a RAID 1 Device In a RAID 1 device each member segment contains its own copy of all of the data stored in the RAID You can add a mirror t...

Page 88: ...4 and 5 can tolerate at least one disk failure Any given RAID can have one spare disk designated for it but the spare itself can serve as the designated spare for one RAID for multiple RAIDs or for a...

Page 89: ...e RAID device 2 In EVMS select the Actions Add Spare Disk to a Region the addspare plug in for the EVMS GUI 3 Select the RAID device you want to manage from the list of Regions then click Next 4 Selec...

Page 90: ...g RAID 4 or 5 the missing data No Spare Exists If the RAID does not have a spare disk the RAID operates in degraded mode until you configure and add a spare When you add the spare the MD driver detect...

Page 91: ...failed device However the working device or devices are listed Hopefully you have a record of which devices were members of the RAID By the process of elimination the failed device is dev sda2 The Sp...

Page 92: ...ble for other use until you remove it from the RAID After you remove it the disk appears in the Available Objects list in the EVMS GUI where it can be used for any purpose NOTE If you pull a disk or i...

Page 93: ...d0 active raid5 sdg1 0 sdk1 4 sdj1 3 sdi1 2 device active not active RAID label you specified storage object RAID order The RAID is active and mounted at dev evms md md0 The RAID label is raid5 The ac...

Page 94: ...nt Update Time Mon Apr 17 05 50 44 2006 State clean degraded Active Devices 4 Working Devices 4 Failed Devices 0 Spare Devices 0 Layout left symmetric Chunk Size 128K UUID 2e686e87 1eb36d02 d3914df8 d...

Page 95: ...h1 2 8 129 2 active sync dev sdi1 3 8 145 3 active sync dev sdj1 4 8 161 4 active sync dev sdk1 6 6 4 Monitoring a Remirror or Reconstruction You can follow the progress of the synchronization or reco...

Page 96: ...d No An md array that was rebuilding is no longer rebuilding either because it finished normally or was aborted syslog priority Warning Fail Yes An active component device of an array has been marked...

Page 97: ...nother if they are in the same spare group and if the destination array has a failed drive but no spares Listing the devices to monitor is optional If any devices are listed on the command line mdadm...

Page 98: ...stop raid device mdadm stop member devices For more information about using mdadm please see the mdadm 8 man page 5 Delete all data on the disk by literally overwriting the entire device with zeroes E...

Page 99: ...allows for additional fault tolerance by using a second independent distributed parity scheme dual parity Even if one of the hard disk drives fails during the data recovery process the system continu...

Page 100: ...or the RAID 6 device dev md0 6 Reboot the server The RAID 6 device is mounted to local 7 Optional Add a hot spare to service the RAID array For example at the command prompt enter mdadm dev md0 a dev...

Page 101: ...member device in the RAID 0 is mirrored individually multiple disk failures can be tolerated and data remains available as long as the disks that fail are in different mirrors You can optionally confi...

Page 102: ...5 Edit the etc mdadm conf file to add entries for the component devices and the RAID device dev md2 6 Edit the etc fstab file to add an entry for the RAID 1 0 device dev md2 7 Reboot the server The R...

Page 103: ...a file system on the RAID 0 1 device dev md2 such as a Reiser file system reiserfs For example at the command prompt enter mkfs reiserfs dev md2 Modify the command if you want to use a different file...

Page 104: ...he effective storage size is the number of devices divided by the number of replicas For example if you specify 2 replicas for an array created with 5 component devices a copy of each block is stored...

Page 105: ...with an odd number of disks and two replicas sda1 sdb1 sdc1 sde1 sdf1 0 0 1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 10 10 11 11 12 Far Layout The far layout stripes data over the early part of all drives th...

Page 106: ...the command prompt enter all on the same line mdadm create dev md3 run level 10 chunk 4 raid devices 4 dev sdf1 dev sdg1 dev sdh1 dev sdi1 4 Create a Reiser file system on the RAID 10 device dev md3...

Page 107: ...he data is now across all devices An example of this process is given in the following procedure 1 Create a degraded RAID 1 device dev md0 using one single drive dev sd1 enter the following at the com...

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Page 109: ...tool supports resizing only for software RAID levels 1 4 5 and 6 These RAID levels provide disk fault tolerance so that one component partition can be removed at a time for resizing In principle it is...

Page 110: ...o or reduced disk fault tolerance Even for RAIDs that can tolerate multiple concurrent disk failures do not remove more than one component partition at a time WARNING If a RAID does not have disk faul...

Page 111: ...essed by the system When the replacement device is added back into the RAID it takes much longer to synchronize the data because all of the data that was on the original device must be rebuilt 5 Re ad...

Page 112: ...e 112 If your array was not resized as you expected you must reboot then try this procedure again 8 2 3 Increasing the Size of the File System After you increase the size of the array see Section 8 2...

Page 113: ...mount command that is specific to the JFS file system mount o remount resize mnt Using the resize option is valid only during a remount when the volume is already mounted read write The mount point i...

Page 114: ...d0 Wait until the resizing is completed before continuing 3 If the file system is not mounted mount it now For example to mount an ReiserFS file system for a RAID named dev md0 at mount point raid ent...

Page 115: ...file system by entering df h The Disk Free df command shows the total size of the disk the number of blocks used and the number of blocks available on the file system The h option print sizes in huma...

Page 116: ...s results if you remove any of its partitions Be very careful when removing partitions and make sure that you have a backup of your data available The procedure in this section uses the device names s...

Page 117: ...have resized each of the component partitions in the RAID the RAID array configuration continues to use the original array size until you force it to be aware of the newly available space You can spe...

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Page 119: ...o the secondary device in a way that ensures that both copies of the data are always identical By default DRBD uses the TCP port 7788 for communications between DRBD nodes The open source version of D...

Page 120: ...onf file on the primary node node1 in a text editor modify the following parameters in the on hostname sections then save the file hostname device disk address meta disk All of these options are expla...

Page 121: ...drbd0 r0mount 1d Create a file from the primary node by entering touch r0mount from_node1 2 Test the DRBD service on node 2 2a Open a terminal console then log in as the root user or equivalent 2b Di...

Page 122: ...on 9 5 1 Configuration on page 122 Section 9 5 2 Host Names on page 122 Section 9 5 3 TCP Port 7788 on page 123 Section 9 5 4 The do what i say Option on page 123 9 5 1 Configuration If the initial dr...

Page 123: ...le in the distribution drbd 8 drbddisk 8 drbdsetup 8 drbdadm 8 drbd conf 5 DRBD org http www drbd org DRBD references at the Linux High Availability Project http linux ha org DRBD by the Linux High Av...

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Page 125: ...ou set up a separate boot boot partition when using multipathing This issue has been resolved in Support Pack 1 and later 10 2 Rescue System Cannot Find Devices That Are Managed by EVMS The Linux resc...

Page 126: ...e proper order each time your servers reboot 10 5 Device Nodes Are Not Automatically Re Created on Restart Effective in SUSE Linux Enterprise 10 the dev directory is on tmpfs and the device nodes are...

Page 127: ...ES 10 SP3 on page 128 Section A 5 May 15 2009 on page 130 Section A 6 November 24 2008 on page 130 Section A 7 June 10 2008 on page 131 Section A 8 March 20 2008 SLES 10 SP2 on page 131 A 1 February 2...

Page 128: ...Configuring Default Multipath Behavior in etc multipath conf on page 58 In the default_getuid command line use the path sbin scsi_id as shown in the above example instead of the sample path of lib ude...

Page 129: ...g Multipath I O for the Root Device on page 67 Added Step 4 on page 68 and Step 6 on page 68 for System Z Section 5 11 Scanning for New Partitioned Devices without Rebooting on page 71 Corrected the s...

Page 130: ...pdates have been applied More specifically you need mkinitrd 1 2 106 61 and multipath tools 0 4 7 34 23 or later However if you install the packages and set up the configuration you might run into upd...

Page 131: ...etc multipath conf File on page 56 Use the v3 option to show the full path list Location Change Section 5 2 7 Supported Architectures for Multipath I O on page 47 This section is new Section 5 2 8 Su...

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