December 14, 2009 at 5:46 am
Many questions there, among them:
1) what is the provenance of the graph they show. who did the benchmark and tuning of each SAN listed?
2) what the heck is "Real FiberChannel"?
3) they are intentionally causing disk fragmentation which will catch up to them once things get busy.
4) they aren't wiping out the blocks that they are leaving behind as they write their new stripes.
5) was their testing fully read, fully write or a mix?
etc.
Best,
Kevin G. Boles
SQL Server Consultant
SQL MVP 2007-2012
TheSQLGuru on googles mail service
December 14, 2009 at 5:51 am
Similar to my own questions :laugh:
It's interesting because we have a NetApp box coming in the next few weeks - just to handle shared drives and such - so it's kinda topical. I came across those links recently and thought they were interesting. Not sure I believe it either, but it's sure to provoke debate.
Paul White
SQLPerformance.com
SQLkiwi blog
@SQL_Kiwi
December 14, 2009 at 10:30 am
TheSQLGuru (12/12/2009)
Curious. I wonder if that improvement came simply because NetApp was doing something 'dumb' with the RAID 5 setup you had. I have heard horror stories from multiple clients who tried NetApp for serving up sql server workloads, so I advise all my clients to steer clear of them for that purpose. Maybe they have improved things recently...
Our NetApp DP was a new purchase - didn't use them with the RAID 5 setup.
Jason...AKA CirqueDeSQLeil
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June 14, 2012 at 6:49 am
You seems to be using a lot of functions on the fields in the select. Most of it is converting DateTime field to 112 format. IS that be avoided. As it would avoid the used of those fileds even if they are part of you index. So if you can configure the datetime to the format you want or do it in the application. Instead of doing here in the query
Regards
Asit
June 14, 2012 at 7:03 am
ASITKAUSHIK (6/14/2012)
You seems to be using a lot of functions on the fields in the select. Most of it is converting DateTime field to 112 format. IS that be avoided. As it would avoid the used of those fileds even if they are part of you index. So if you can configure the datetime to the format you want or do it in the application. Instead of doing here in the queryRegards
Asit
That's not correct. The functions are not involved in any filtering (WHERE or ON clauses) so they won't have any affect on index selection and usage.
Jack Corbett
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June 14, 2012 at 7:12 am
No but using that function on the data would require some resources and would be a costly affair. I recommend first just test the result and execution plan of the query removing the convert function. I think it should give a performance impact.
June 14, 2012 at 7:15 am
Please note: 3 year old problem.
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
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