IBM DCS3860, Инструкция по установке, использованию и обслуживанию

Страница: 113 / 204

v
How many DDMs exist in an array. Replacing DDMs one at a time is better
suited for arrays consisting of 3 to 5 DDMs. If you have more than 10 DDMs,
consider replacing all of them at the same time.
v
How much risk of losing data is acceptable. Because the array will be in a
degraded state during the RAID array reconstruction and copyback process as
result of replacing a DDM in the array, any new DDM 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 extensive are the changes to the data while the array is in a degraded state
during the RAID array reconstruction and copyback process as result of
replacing an DDM in the array. More extensive the data changes, more work is
needed to restore the data in the event of an array failure due to an additional
DDM failure.
Replacing all DDMs at the same time
Use this method if you are upgrading DDMs containing RAID 0 logical drives. All
data currently on the DDMs is lost when you replace them. Therefore, you must
back up all data that is currently on the DDMs. Turn off the DCS3860 storage
system, so that it is inaccessible to other users.
Before you begin, review the following information:
v
“Replacing multiple DDMs” on page 94, particularly the differences between the
two possible upgrade procedures
v
The software documentation regarding DDM upgrades and installation
v
The documentation that is shipped with the new DDMs
Read all precautionary notes, kit instructions, and other information. Kit
instructions often contain the most current information about the DDMs and
their installation, upgrade, or servicing procedures. Compare the kit instructions
with this procedure to determine if you need to modify this procedure.
Complete the following steps to replace all the DDMs at the same time:
1. Use the IBM DS Storage Manager software to check the status of the DCS3860.
Correct any problems that are reported.
2. Back up data on the DDMs that you are replacing.
You need the backup to restore data on the DDMs 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 26.
3. Unpack the new DDMs.
Set the DDMs on a dry, level surface away from magnetic fields. Save the
packing material and documentation in case you need to return them.
4. Complete the following steps:
a. Stop all I/O activity to the storage system and attached storage expansion
enclosures.
v
All of the green Drive activity LEDs on the front of the storage system
are not flashing.
v
The Cache active LEDs are off. Refer to “Checking the LEDs” on page
61 for the location of the Cache active LEDs.
b. If applicable, use the operating system software to disconnect the storage
system logical drives from the host before you power off the storage
system.
Chapter 5. Replacing components
95