Hitachi Compute Blade 2000 User Manual page 408

Click Next.
9
The following screen appears:
10 Specify the RAID level, stripe size, read policy, write policy, and disk array size.
When enabling the write cache of the disk array with the equipment that has no
cache backup module installed, connect the system equipment to UPS. When
you use the equipment without connecting to the UPS, data can disappear and
be corrupted.
Set each item to the values in the following table.
Item
RAID Level *1 *2 RAID Level
Stripe Size *3 Stripe size
(only RAID 0 and 5)
Access Policy Access policy
Read Policy Read policy
Write Policy *4 *5 Write policy
IO Policy Read-cache operation
Drive Cache Setting the hard disk
cache
NOTICE
Content
Specify any level.
8 KB / 16 KB
512 KB / 1 MB
[RW (reading and writing)] /
Read Only (reading only)
Blocked (access denied)
[Normal (no advance reading)] /
Ahead (always advance reading)
Without cache backup module installed * 7: [Write
Through (write cache invalid)] /
Always Write Back (write-cache valid) / Write Back
with BBU (Write cache is valid only when the battery
is installed.)
With cache backup module installed * 8:
Through (write-cache invalid)/ Always Write Back
(write-cache
is valid only when a cache backup module is
installed.)]
[Direct (reading from the cache at a cache hit)] /
Cached (always reading from the cache)
[Disable (setting invalid)]
No change (depending on the hard disk setting)
357
Setting value **
/ 32 KB / [64 KB] / 128 KB / 256 KB /
/
valid)/[Write Back With BBU (Write cache
/ Enable (setting valid)
Write
/