thread881-1416624 - I came across thread881-1416624 and although it is a closed thread I wanted to provide an update in case anyone has a similar question. The original question was how to free space back to a Compellent SAN when the highwater mark has been reached?
In February 2008 Compellent introduced Storage Center 4.0 which includes the Free Space Recovery feature. With this feature you no longer have to recreate and restore your volume to gain back the free space to the SAN. This is an agent you run on Windows servers. The agent can be set up to run automatically on a scheduled basis (weekly is good) to recover free space back to the SAN pool.
Another best practice is to run Diskeeper 2010 once per week. If you run it more frequently than once per week the Compellent SAN will mark frequently defragmented blocks as busy and will therefore place those blocks on higher tiers of storage. What you really want is to move blocks to higher tiers based on frequency of user access, not frequncy of data defragmentation. Defragmentation will keep IO's related to file fragmentation to a minimum (saves power and improve performance). Defragmenting will also keep the thin provisioning high water mark from growing too large.
One final note related to thin provisioning is, when setting up virtual servers, use Raw Device Mapping. Otherwise you won't be able to run Free Space Recovery.
Good Luck!
In February 2008 Compellent introduced Storage Center 4.0 which includes the Free Space Recovery feature. With this feature you no longer have to recreate and restore your volume to gain back the free space to the SAN. This is an agent you run on Windows servers. The agent can be set up to run automatically on a scheduled basis (weekly is good) to recover free space back to the SAN pool.
Another best practice is to run Diskeeper 2010 once per week. If you run it more frequently than once per week the Compellent SAN will mark frequently defragmented blocks as busy and will therefore place those blocks on higher tiers of storage. What you really want is to move blocks to higher tiers based on frequency of user access, not frequncy of data defragmentation. Defragmentation will keep IO's related to file fragmentation to a minimum (saves power and improve performance). Defragmenting will also keep the thin provisioning high water mark from growing too large.
One final note related to thin provisioning is, when setting up virtual servers, use Raw Device Mapping. Otherwise you won't be able to run Free Space Recovery.
Good Luck!
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