Re: Performance and I/O

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Nilo Segura Chinchilla                    *   e-mail nilo_at_cernvm.cern.ch
Computing and Network Division            *          nilo_at_sundb02.cern.ch 
European Laboratory for Particle Physics  *   phone +41 +22 7674943       
Geneva - Switzerland                      *   


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  "I amIn article <781732709snz_at_tomcooke.demon.co.uk>, tom_at_tomcooke.demon.co.uk (Tom Cooke) writes:


**In article <36q9p1$hsr_at_news.delphi.com>


**           dagmara_at_news.delphi.com "DAGMARA_at_DELPHI.COM" writes:

**

**> I have experienced about 10-20% gain using raw partitions on UNIX servers 

**> with version 6.  I have not seen any gain by going raw with version. 7.  

**> 

**> My advice: tune your SQL statements, review your data architecture and 

**> adjust accordingly.  Unless you have an extremely astute UNIX system 

**> administrator, and an excellent backup and recovery procedure, and have 

**> tried everything else but you still need to squeeze higher performance 

**> from your application, do not use raw partitions.

**> 

**I agree with all your comments about tuning, data architecture, how on-the-

**ball the sysadmin is, having good backup/recover procedures etc; however,

**raw disk has at least two possible advantages; async IO, and any system-

**specific facilities for fast disk-to-tape copy (e.g. Pyramid's ?rdcp)

**--   


 Well, OracleV7 for Solaris 2.3 offers you async IO using ufs ( before, raw
devices were needed for it).

 Also, in IOUW94 it was said that in 7.1.4 they have rewritten the I/O 
routines to reduce the gap between ufs and raw devices. This was said
by Ken Jacobs, the RDBMS boss. So....

       regards..




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Nilo Segura Chinchilla                    *   e-mail nilo_at_cernvm.cern.ch
Computing and Network Division            *          nilo_at_sundb02.cern.ch 
European Laboratory for Particle Physics  *   phone +41 +22 7674943       
Geneva - Switzerland                      *   


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 "I am the one who steps from the shadows" - John Constantine


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