Apple Xsan 2 - Manual (Page 83)

Chapter 5 Manage SAN storage 83
Change the Windows ID mapping
If you have Windows clients on your SAN, the Windows ID Mapping setting determines
how they map user and group information to the Xsan-compatible user IDs and group
IDs they need in order to access this volume. For more information, see “Map Windows
user and group IDs” on page 100.
Change advanced allocation and cache settings
Volume settings that control the allocation of space for growing files and the caching
of file-related data structures are set by Xsan Admin to suit the type of volume you
set up. If necessary, you can use Xsan Admin to adjust these advanced allocation and
caching settings for a volume.
Important: Do not adjust these settings unless you understand their role in volume
performance or you are directed to change them by Apple support personnel.
Change advanced volume settings:
In Xsan Admin, select Volumes in the SAN Assets list, select the volume, choose Edit
m
Volume Settings from the Action pop-up menu (gear), and then specify:
File Expansion Min: The number of storage blocks added to the file for the first
expansion request.
File Expansion Increment: The number of storage blocks by which the expansion
request is increased for each subsequent request.
File Expansion Max: The maximum expansion request that’s allowed.
Inode Cache Size: The maximum number of inode data structures that can be cached
on the volume by the metadata controller.
Buffer Cache Size: The amount of memory that the metadata controller can allocate
for storing a volume’s metadata.
Note: Changing advanced volume settings causes the volume to restart.
Change storage pool settings
The SAN Setup assistant chooses storage pool settings based on the type of volume
you use them on. To specify storage pool settings yourself, choose an affinity tag
or storage pool in the Configure Volume Affinities pane of the SAN Setup assistant
when you create a volume, or when you add a storage pool to a volume, and click the
Settings button below the list.
The best way to set up a SAN is to plan its organization carefully before you set it up,
including settings for the storage pools that make up its volumes. To change storage
pool settings for an existing volume, you must destroy and recreate the volume.