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Chapter 7: Caching
Upgrading CHALLENGE RAID to Support Caching
Please note these points before you enable caching:
•
Because disk modules are required in slots A0, B0, C0, D0, and E0 for
caching, you might need to add disk modules to your storage system.
See “Updating the Disk Module Firmware” in Chapter 5.
•
If you add or move disk modules, you need to bind them into new
physical disks or change the existing physical disk units to include
them; see “Binding Disks Into RAID Units,” in Chapter 4.
•
Do not move a disk module to another slot unless it is absolutely
necessary to do so. Never move disk modules from slots A0, A3, B0, C0,
D0, and E0.
•
Set up caching on one SP at a time.
Once the necessary hardware components have been installed, follow these
steps to set up caching:
1.
Enable the read and write caches for the physical disk units that will
use caching:
/usr/raid5/raid5 -d
device
chglun -l
lun-number
read
or
/usr/raid5/raid5 -d
device
chglun -l
lun-number
write
or
/usr/raid5/raid5 -d
device
chglun -l
lun-number
rw
2.
Specify the cache page size and cache size parameters.
3.
Enable storage system caching with raid5 -d device getcache, as explained
in “Setting Cache Parameters,” earlier in this chapter.
