HP XP7 Provisioning for Open Systems User Guide (H6F56-96009)

Pool Capacity ConsumedMetadata WritingFile SystemOS
effectiveness of reducing the pool
capacity consumption decreases.
OWrites metadata in Allocation
Group Size intervals.
XFSLinux
Depends upon allocation group size.
The amount of pool space consumed
will be approximately [THP V-VOL
Size]*[42 MB/Allocation Group Size]
OWrites metadata in 128-MB
increments.
Ext2
Ext3 About 33% of the size of the THP
V-VOL.
The default block size for these file
systems is 4 KB. This results in 33% of
the THP V-VOL acquiring THP pool
pages. If the file system block size is
changed to 2 KB or less then the THP
V-VOL Page consumption becomes
100%.
XWrites metadata in 52-MB
increments.
UFSSolaris
Size of THP V-VOL.
OWrites metadata to the first
block.
VxFS
Small (one page).
XWrites metadata in 8-MB
increments.
JFSAIX
Size of THP V-VOL.
If you change the Allocation Group
Size settings when you create the file
system, the metadata can be written
to a maximum interval of 64 MB.
Approximately 65% of the pool is
used at the higher group size setting.
OWrites metadata to the first
block.
JFS2
Small (one page).
OWrites metadata to the first
block.
VxFS
Small (one page).
OWrites metadata to the first
block.
JFS (VxFs)HP-UX
Small (one page).
XWrites metadata in 10-MB
increments.
HFS
Size of THP V-VOL.
Explanatory notes:
O: Indicates an effective reduction of pool capacity.
X: Indicates no effective reduction of pool capacity.
*See “Formatting LDEVs in a Windows environment” (page 136)
66 Configuring thin provisioning