Storage Decisions

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Storage Decisions

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465789psw Hall of Fame Points: 3314 More actions · Answer 1

create a lun for temp DB ,make sure you create on file per core and set the size of each of them to the same at startup, 2005+ uses temp a lot temp DB

one LUN for transaction log

one LUN for DB

one LUN for SQL -- although you could run it off server...I generally create a lun for it

you can always add an exra lun later and split the DB if need

your is simple link that might help a bit

http://technet.microsoft.com/en-us/library/cc966534.aspx

ldstpete SSC Rookie Points: 44 More actions · Answer 2

Thanks for the reply. I originally thought about doing that, but I cannot guarantee that the LUNS are not going to be shared. I also heard that DAS can be faster in some cases (especially when the LUNs are RAID 5 and shared) so where can that come into play?

thanks!

465789psw Hall of Fame Points: 3314 More actions · Answer 3

well a couple of things, the SAN has lots of cache...and SQL uses that by using read ahead, this helps a bunch, the engine will go out an start grabing pages that is thinks it will need even before the I/O is asked for. Second thing is when using a SAN you can get away with much more fragmentation and page splits then via the server

Linchi Shea -- had about 5 articles on fragmentation on a SAN, surprising when you rebuild an index on SAN you see very very little improvement...due to the cache and read ahead issue.

so I would say go with the SAN. also keep in mine that your SAN has a lot more spindles then your Server this will help.

on ? you said the San ADMIN will not change over to 10 from 5 is there something being used on the LUN's now. Maybe he has empty luns at the moment?

anyhow read Luchi blogs and after such I am guess you will go with the SAN ...I have also included an counter argument to read.....good luck

http://sqlblog.com/search/SearchResults.aspx?q=fragmentation

http://kendalvandyke.blogspot.com/2009/02/disk-performance-hands-on-part-5-raid.html

ldstpete SSC Rookie Points: 44 More actions · Answer 4

Unfortunately, he (and management) do not believe we need RAID 10. They don't think we would gain much for the disk cost because we are a small to midlevel organization (3000 users). We also have an Oracle ebusiness suite infrastructure running on the same SAN serving a couple of thousand users - they think that its performance on RAID 5 is acceptable, so in their mind there is no reason to change for a "little SQL box" such as this one.

I will go ahead and plan for LUN usage for all components, but probably keep the program files on the DAS.