Novell Open Enterprise Server 2, System Administration Manual, Page: 44 / 55

44 OES 2: NetWare Traditional File System Administration Guide
no
vd
ocx
(e
n)
6 Ap
ril 20
07
Keep at least 1000 free blocks on each Traditional volume that has suballocation enabled. Free
blocks are disk blocks that have no files stored in them. If the number of free blocks is low, the
suballocation increases server utilization. To view the number of free blocks, view the volume’s
details in iManager.
7.1.2 Disable Read-After-Write-Verify
Disable Read-After-Write-Verify in the Monitor (
monitor
) utility if your hard disk provides this
capability.
Read-After-Write-Verify is almost always provided by the hard disk itself. Use the Read-After-
Write-Verify feature only if your hardware does not provide this feature but does support software-
controlled Read-After-Write-Verify.
For information, see Section 7.3.3, “Turn Off Read-After-Write Verification,” on page 47 .
7.1.3 For 16-Bit Disk Adapters, Increase the Number of
Reserved Buffers Below 16 MB
If you have a 16-bit disk adapter, make sure you increase the number of reserved buffers below 16
MB. Use the
set
command or the Monitor (
monitor
) utility to set the Reserved Buffers Below 16
MB parameter to its upper limit, 300. The parameter is found in Monitor > Available Options >
Server Parameters > Memory . For instructions, see “ SET ” in the OES 2: Utilities Reference .
Remember that too many reserved buffers can prevent large volumes from mounting in a Traditional
file system. As soon as possible, upgrade the system to a newer board that can access higher
memory.
7.1.4 Use Drivers that Support Scatter/Gather Functionality
Scatter/gather is an I/O technique to organize the read and write calls from multiple data buffers that
are separated in memory. The purpose is to lower the overhead associated with each call by reducing
the number of calls that must be made.
7.1.5 Provide a Disk Large Enough for a Memory Core Dump
Provide a device that is large enough to hold a core dump of the server’s memory. A core dump
cannot span multiple devices.
7.1.6 Select Segments for Volumes from Different Disks
If a volume comprises two or more segments, each segment should be on a different disk. If the
volume is made of more than one segment on one disk, the volume spans between the two segments,
slowing performance.
7.1.7 Monitor Free Space in Volumes
Keep at least 10% free space in any NetWare volume, except for the sys: volume, where there
should be 20% free space.