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02-27-2008, 12:10 PM
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 Raid 5 or Raid 10? DB2 LUW v8.2 FP 14 RHAS 2.1 Not trying to start a flame war or anything, but does anyone have an opinion regarding whether to use Raid 5 or Raid 10 w/ DB2? We have an EMC SAN (a Clariion CX600 I believe). My SysAdmin and I are discussing which raid type to use. Several years ago during my Informix DBA days, Art Kagel and other well-informed folks on C.D.I. would occasionally point out how raid 5 w/ database is a BAD idea, and how raid 10 should always be used. With SAN advances (cache, memory, speed, etc..), does this still apply? My SysAdmin thinks Raid 5 is a better way to go. All of my tablespace containers are DMS (typically 2 gigabytes each), except for temp space, which are SMS. TIA aj      |
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02-27-2008, 12:10 PM
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| Re: Raid 5 or Raid 10? On Apr 16, 8:54 am, aj <ron...@mcdonalds.com> wrote: > DB2 LUW v8.2 FP 14 RHAS 2.1 > > Not trying to start a flame war or anything, but does anyone have an > opinion regarding whether to use Raid 5 or Raid 10 w/ DB2? > > We have an EMC SAN (a Clariion CX600 I believe). My SysAdmin and I > are discussing which raid type to use. Several years ago during my > Informix DBA days, Art Kagel and other well-informed folks on C.D.I. > would occasionally point out how raid 5 w/ database is a BAD idea, and > how raid 10 should always be used. > > With SAN advances (cache, memory, speed, etc..), does this still apply? > My SysAdmin thinks Raid 5 is a better way to go. > > All of my tablespace containers are DMS (typically 2 gigabytes each), > except for temp space, which are SMS. > > TIA > > aj http://www.acnc.com/04_01_10.html |
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02-27-2008, 12:10 PM
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| Re: Raid 5 or Raid 10? On Apr 16, 8:54 am, aj <ron...@mcdonalds.com> wrote: > DB2 LUW v8.2 FP 14 RHAS 2.1 > > Not trying to start a flame war or anything, but does anyone have an > opinion regarding whether to use Raid 5 or Raid 10 w/ DB2? > > We have an EMC SAN (a Clariion CX600 I believe). My SysAdmin and I > are discussing which raid type to use. Several years ago during my > Informix DBA days, Art Kagel and other well-informed folks on C.D.I. > would occasionally point out how raid 5 w/ database is a BAD idea, and > how raid 10 should always be used. > > With SAN advances (cache, memory, speed, etc..), does this still apply? > My SysAdmin thinks Raid 5 is a better way to go. > > All of my tablespace containers are DMS (typically 2 gigabytes each), > except for temp space, which are SMS. > > TIA > > aj RAID 10 is still the better way to go for a database with a lot of writes. For something like a data warehouse it might not be so critical. |
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02-27-2008, 12:10 PM
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| Re: Raid 5 or Raid 10? If the Clariion CX600 issues writes to cache and performs the physical write asynchronously, does the stated benefit of raid 10 versus 5 really exists? On Apr 16, 10:29 am, "Ray" <raymmailbox-n...@yahoo.com> wrote: > On Apr 16, 8:54 am, aj <ron...@mcdonalds.com> wrote: > > > > > > > DB2 LUW v8.2 FP 14 RHAS 2.1 > > > Not trying to start a flame war or anything, but does anyone have an > > opinion regarding whether to use Raid 5 or Raid 10 w/ DB2? > > > We have an EMC SAN (a Clariion CX600 I believe). My SysAdmin and I > > are discussing which raid type to use. Several years ago during my > > Informix DBA days, Art Kagel and other well-informed folks on C.D.I. > > would occasionally point out how raid 5 w/ database is a BAD idea, and > > how raid 10 should always be used. > > > With SAN advances (cache, memory, speed, etc..), does this still apply? > > My SysAdmin thinks Raid 5 is a better way to go. > > > All of my tablespace containers are DMS (typically 2 gigabytes each), > > except for temp space, which are SMS. > > > TIA > > > aj > > RAID 10 is still the better way to go for a database with a lot of > writes. For something like a data warehouse it might not be so > critical.- Hide quoted text - > > - Show quoted text - |
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02-27-2008, 12:10 PM
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| Re: Raid 5 or Raid 10? aj wrote: > DB2 LUW v8.2 FP 14 RHAS 2.1 > > Not trying to start a flame war or anything, but does anyone have an > opinion regarding whether to use Raid 5 or Raid 10 w/ DB2? > > We have an EMC SAN (a Clariion CX600 I believe). My SysAdmin and I > are discussing which raid type to use. Several years ago during my > Informix DBA days, Art Kagel and other well-informed folks on C.D.I. > would occasionally point out how raid 5 w/ database is a BAD idea, and > how raid 10 should always be used. > > With SAN advances (cache, memory, speed, etc..), does this still apply? > My SysAdmin thinks Raid 5 is a better way to go. NO RAID5!!! NO RAID5!!! NO RAID5!!! NO RAID5!!! NO RAID5!!! NO RAID5!!! This is still true and likely always will be. Performance asside (and noone's proven to me yet that massive cache eliminates more than half of the RAID5 write penalty) the data safety issues are HUGE and noone's solved them yet (only DG - now part of EMC - tried and their solution didn't work). At the cost of drives today RAID5 no longer makes sense! Please read ALL of the related articles posted on www.baarf.com, including my own, and read the comments on the 'Baarf members' page from the many who've been bitten, and see why everyone, not just DBAs, should avoid RAID5 like the plague. > All of my tablespace containers are DMS (typically 2 gigabytes each), > except for temp space, which are SMS. Art S. Kagel NO RAID5!!! NO RAID5!!! NO RAID5!!! NO RAID5!!! NO RAID5!!! NO RAID5!!! |
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02-27-2008, 12:10 PM
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| Re: Raid 5 or Raid 10? Thanks Art. I was kinda hoping you'd chime in.  cheers aj Art S. Kagel wrote: > aj wrote: >> DB2 LUW v8.2 FP 14 RHAS 2.1 >> >> Not trying to start a flame war or anything, but does anyone have an >> opinion regarding whether to use Raid 5 or Raid 10 w/ DB2? >> >> We have an EMC SAN (a Clariion CX600 I believe). My SysAdmin and I >> are discussing which raid type to use. Several years ago during my >> Informix DBA days, Art Kagel and other well-informed folks on C.D.I. >> would occasionally point out how raid 5 w/ database is a BAD idea, and >> how raid 10 should always be used. >> >> With SAN advances (cache, memory, speed, etc..), does this still apply? >> My SysAdmin thinks Raid 5 is a better way to go. > > NO RAID5!!! NO RAID5!!! NO RAID5!!! NO RAID5!!! NO RAID5!!! NO > RAID5!!! > > This is still true and likely always will be. Performance asside (and > noone's proven to me yet that massive cache eliminates more than half of > the RAID5 write penalty) the data safety issues are HUGE and noone's > solved them yet (only DG - now part of EMC - tried and their solution > didn't work). At the cost of drives today RAID5 no longer makes sense! > Please read ALL of the related articles posted on www.baarf.com, > including my own, and read the comments on the 'Baarf members' page from > the many who've been bitten, and see why everyone, not just DBAs, should > avoid RAID5 like the plague. > >> All of my tablespace containers are DMS (typically 2 gigabytes each), >> except for temp space, which are SMS. > > Art S. Kagel > > NO RAID5!!! NO RAID5!!! NO RAID5!!! NO RAID5!!! NO RAID5!!! NO > RAID5!!! |
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02-27-2008, 12:10 PM
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| Re: Raid 5 or Raid 10? tsmithnj@gmail.com wrote: > If the Clariion CX600 issues writes to cache and performs the physical > write asynchronously, does the stated benefit of raid 10 versus 5 > really exists? Tested it on Clariion myself several years back, so I recommend, as always, that you test it YOURSELF, but, yes the RAID5 write penalty is supressed or hidden by massive caching by about 50% but ONLY if your write volume doesn't exceed the write throughput of the array over some time period. Then performance reverts to non-cached performance. And the data safety issue is the big one for me, NOT the performance. RAID5 is NOT SAFE! Art S. Kagel > On Apr 16, 10:29 am, "Ray" <raymmailbox-n...@yahoo.com> wrote: > >>On Apr 16, 8:54 am, aj <ron...@mcdonalds.com> wrote: >> >> >> >> >> >> >>>DB2 LUW v8.2 FP 14 RHAS 2.1 >> >>>Not trying to start a flame war or anything, but does anyone have an >>>opinion regarding whether to use Raid 5 or Raid 10 w/ DB2? >> >>>We have an EMC SAN (a Clariion CX600 I believe). My SysAdmin and I >>>are discussing which raid type to use. Several years ago during my >>>Informix DBA days, Art Kagel and other well-informed folks on C.D.I. >>>would occasionally point out how raid 5 w/ database is a BAD idea, and >>>how raid 10 should always be used. >> >>>With SAN advances (cache, memory, speed, etc..), does this still apply? >>>My SysAdmin thinks Raid 5 is a better way to go. >> >>>All of my tablespace containers are DMS (typically 2 gigabytes each), >>>except for temp space, which are SMS. >> >>>TIA >> >>>aj >> >>RAID 10 is still the better way to go for a database with a lot of >>writes. For something like a data warehouse it might not be so >>critical.- Hide quoted text - >> >>- Show quoted text - > > > |
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