IBM System Storage DS3300, Installation, User'S, And Maintenance Manual

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v
How much downtime is acceptable as you swap the drives.
v The number of drives in an array. Replacing drives one at a time is better suited
to arrays that consist of three to five drives. If you have more than 10 drives,
consider replacing all drives at the same time.
v
How much risk of losing data is acceptable. Because the array is in a degraded
state during the RAID array reconstruction and copyback process as result of
replacing a drive in the array, any new drive failure will cause the array to fail
(causing a loss of data availability and even a loss of data). The duration of the
reconstruction and copyback process can be quite long, depending on the size of
the RAID array.
v
How extensively the data will be changed while the array is in a degraded state
during the RAID array reconstruction and copyback process as a result of
replacing a drive in the array. The more extensive the data changes are, the
more work that will have to be performed to restore the data in the event that the
array fails because an additional drive fails while the array is in a degraded state.
Replacing all drives at the same time
Use this procedure to replace all drives at the same time. You must use this method
if you are upgrading drives that contain RAID 0 logical drives. All the data that is
currently on the drives is lost when you replace the drives; therefore, you must back
up all data that is currently on the drives. This procedure also requires you to turn
off the storage expansion enclosures and the DS3300, which makes the storage
subsystem (and any attached storage expansion enclosures) inaccessible to other
users.
Attention: After you remove a drive, wait 70 seconds to allow the drive to spin
down before you replace or reseat the drive. Failure to do so might cause
unpredictable results.
To replace all the drives at the same time, complete the following steps:
1. Read the following information:
v The information in “Replacing multiple drives” on page 74, particularly the
paragraphs that explain the differences between the two possible upgrade
procedures
v
The information in the software documentation about drive upgrades and
installation
v The documentation that comes with the new drives
Read all precautionary notes, kit instructions, and other information. Kit
instructions often contain the most current information about the drives and
their installation, plus upgrade or servicing procedures. Compare the kit
instructions with this procedure to determine whether you must modify this
procedure.
2. Use the DS3000 Storage Manager software to check the status of the
DS3300. Correct any problems that are reported.
3. Perform a complete backup of the drives that you are replacing.
You need the backup to restore data on the drives later in this procedure.
Attention: When you handle static-sensitive devices, take precautions to
avoid damage from static electricity. For details about handling static-sensitive
devices, see “Handling static-sensitive devices” on page 19.
4. Unpack the new drives.
Set the drives on a dry, level surface away from magnetic fields. Save the
packing material and documentation in case you have to return the drives.
Chapter 5. Replacing components
75