TSM v7 db and active log raid 10.. then add SSD

[stephrf]

we plan to use Raid 10 for V6/7 TSM DB and active log.

However, we may incorporate SSD via easytier on V7000 to improve performance
What raid do you use for SSD? I initially thought Raid 5 when I thought it was a kind of flash.
However, it migrates hot blocks. Raid 10 may prove rather pricey for SSD with hot spares!

I'd be interested to hear any thoughts or advice.

thanks rob

 

[marclant]

Here is some info:
http://www-01.ibm.com/support/knowl...com.ibm.itsm.perf.doc/r_chklist_srvdbdsk.html

I strongly recommend that you do not use tiered storage with only hot blocks on SSD. Due to the nature of how TSM works, it's not predictable to determine what blocks will be needed next. I had a customer doing that and they had bad performance because as TSM was using the database for large queries or updates(client backup, expiration, reclamation), the disk subsystem would always identify new hot spots to be moved. The problem is that it needs to be on fast disk before it's needed, by the time it's migrated to SSD, TSM is often done with that block.

 

[stephrf]

Hi, thanks for the response and link. Rob