Accusys ExaSAN SW-08 - Manual (Page 73)

6. Xsan
User Guide Page 6-22
e. Click “Continue” to un-mount and stop the volume, add the new storage pool, and re-mount the
expanded volume.
4. Repeat this process if necessary. You may add up to 3 RAID storage systems in an ExaSAN network,
as illustrated below.
You may change the allocation strategy of a volume, and choose how storage for new files or additional
storage for existing files is allocated on the storage pools that belong to the volume.
Note that once you’ve properly added the LUN, you may verify it by checking if the new LUN can be
discovered on all the hosts in “System Profiler > SCSI Parallel.”
To change the allocation strategy:
1. In Xsan Admin, select “Volumes” in the “SAN Assets” list.
2. Select the volume in the list and choose “Edit Volume Settings” from the “Action” (gear) pop-up
menu.
3. Choose an allocation strategy from the pop-up menu:
• Round Robin (recommended): Each new request for space is assigned to the next available
storage pool in the volume.
• Fill: All data is stored on the first storage pool until it is full, then on the next storage pool, and so
on.
• Balance: New data is written to the storage pool that has the most available free space.
4. Click “OK.”
6.7.2 Performance Optimized ExaSAN Configuration
To achieve maximum Xsan volume performance, it is recommended that you configure the LUNs and
storage pools as illustrated below. This configuration requires three ExaSAN RAID systems, one RAID is
dedicated for metadata LUN, and the other two RAID systems are for data LUNs in the same Storage
Pool. All LUNs are initialized to be RAID 5 by using ExaSAN Quick Setup (refer to Section 4.2.2.1).