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Home -> Community -> Mailing Lists -> Oracle-L -> RE: db datafiles on NetApp FAS940 filer
Carmen,
A number of good points have already been said. I would like to add a word of caution in addition: NetApp uses WAFL - Write Anywhere File Layout. Basically, what this means is that that updates to existing blocks are written to the NetApp 'disks' as _new_ blocks, leading to some interesting side-effects. If your Application is write-intensive (including writes to TEMP on account of Hash joins, sorting, etc. as well as writes to Rollback and Redo which can get intensive), you will find that the Disk space consumed auto-magically blooms very quickly indeed. A NetApp 'snapshot' apparently puts this all back, releasing space by replacing the older, updated blocks with the newer versions (apparently by cleverly updating an internal inode structure). Based on this, you will have to very carefully configure your snapshotting frequency. I do not know the internals of NetApp and the overhead of configuring and executing these snapshots, so YMMV. So... As an outsider, I would suggest that you place the Control files, Redo Logs, TEMP, RBS (or UNDO TBS) and other *update*-intensive objects on Direct Attached Storage (or SANs if you can manage that) to mitigate this, and press the NetApps folks to carefully consider snapshotting. Note that I did not mention Archive logs or temporary staging areas in this list - the disk blocks being written in this case aren't *updates* to existing disk blocks [NAS Gurus - please correct me if I err!]
OTOH, you might want to consider a combined SAN-NAS configuration (seems this is becoming available), where you will be able to get a SAN that will support I/O intensive apps while also serving out NAS via NetApp. You should then be able to get some SAN space for the above files and some NAS space for the rest.
John Kanagaraj
DB Soft Inc
Phone: 408-970-7002 (W)
Disappointment is inevitable, but Discouragement is optional!
>-----Original Message-----
>From: oracle-l-bounce_at_freelists.org
>[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Joze Senegacnik
>Sent: Tuesday, February 10, 2004 12:31 PM
>To: 'oracle-l_at_freelists.org'
>Subject: RE: db datafiles on NetApp FAS940 filer
>
>
>Carmen,
>I know one unhappy customer with NetApp. This customer is using Baan.
>The average wait time for I/O is:
>
>db file sequential read 13.7ms
>db file scattered read 17.9ms
>
>The response time in average consists of: 15% of service time
>and 85% of
>wait time due to slow I/O. They complain that the average CPU
>load is only
>15-20%. They have also problem with unhappy final users. The
>supplier tried
>to improve the performance but with no major change. If
>somebody would ask
>me for the advice about NetApp I wouldn't recommend it.
>
>Joze
>
>
>-----Original Message-----
>From: Carmen Rusu [mailto:carmen.rusu_at_rrc.state.tx.us]
>Sent: Tuesday, February 10, 2004 8:55 PM
>To: oracle-l_at_freelists.org
>Cc: Carmen Rusu
>Subject: db datafiles on NetApp FAS940 filer
>
>
>
>I am experimenting with creating tablespaces/datafiles on a new NetApp
>filer we got installed.
>
>The sysadmin configured a dedicated volume out the the 9tb behemoth
>with a stripe size of 128k, which he tells me is what tech support told
>him to.
>
>Anybody on the list with a NetApp storage device with Oracle on it? How
>did you configure it? Wha kind of performance do you get? Any caveats?
>
>Thanks,
>
>Carmen Rusu
>DBA
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-- Archives are at http://www.freelists.org/archives/oracle-l/ FAQ is at http://www.freelists.org/help/fom-serve/cache/1.html -----------------------------------------------------------------Received on Tue Feb 10 2004 - 18:51:06 CST
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