Below is my customers issue. I am stuck on this one. I would appreciate
if someone could help me out on this. Thanks in advance!
ZFS Checksum feature:
I/O checksum is one of the main ZFS features; however, there is also
block checksum done by Oracle. This is
good when utilizing UFS since it does not do checksums, but with ZFS it
can be a waste of CPU time.
Suggestions have been made to change the Oracle db_block_checksum
parameter to false which may give
Significant performance gain on ZFS.
What are Sun''s stance and/or suggestions on making this change on the
ZFS side as well as making the changes on the Oracle side.
--
Scott MacDonald - Sun Support Services
--------------------------------------------------------------------------------------------------------------------------------------------
_/_/_/_/ _/ _/ _/_/_/ Technical Support Engineer
_/ _/ _/ _/ _/
_/_/ _/ _/ _/ _/ Mon - Fri 8:00am - 4:30pm EST
_/ _/ _/ _/ _/ Ph: 1-800-872-4786 (option 2 & case #)
_/_/_/_/ _/_/_/ _/ _/ email: Scott.M at Sun.com
M I C R O S Y S T E M S alias: s-m at Sun.com
www.sun.com/service/support
--------------------------------------------------------------------------------------------------------------------------------------------
If you need immediate assistance please call 1-800-USA-4-SUN, option 2
and the case number. If I am unavailable, and you need immediate
assistance, please press 0 for more options.
To track package delivery, call Logistics at 1(800)USA-1SUN, option 1
Thank you for using SUN.
Scott Macdonald - Sun Microsystem wrote:> Below is my customers issue. I am stuck on this one. I would appreciate > if someone could help me out on this. Thanks in advance! > > > > ZFS Checksum feature: > > I/O checksum is one of the main ZFS features; however, there is also > block checksum done by Oracle. This is > good when utilizing UFS since it does not do checksums, but with ZFS it > can be a waste of CPU time. > Suggestions have been made to change the Oracle db_block_checksum > parameter to false which may give > Significant performance gain on ZFS. > > What are Sun''s stance and/or suggestions on making this change on the > ZFS side as well as making the changes on the Oracle side. > >I don''t think it is appropriate for Sun to take a stance. Data integrity is more important than performance for many people, so let them decide to make that trade-off. It should be noted that for performance benchmarking, it is not uncommon for checksums to be disabled, since it is a competitive environment where performance is all that matters. That isn''t the real world. In the ZFS case, a checksum mismatch for a redundant configuration will result in an attempt to correct the data. In other words, the checksum is an integral part of the redundancy check. Disabling the checksum will mean that only I/O errors are corrected -- a subset of the possible problems. This plays into the overall risk structure of the system implementation because not only do you have to worry about faults, but now you have to worry about propagation paths for the faults through at least 3 major pieces of software. The trade-off is not simply a data corruption, but also isolation of data corruption. This is not the typical level of analysis I see in our customer base. -- richard
Don''t take my words as an expert advice, as I am newbie when it comes
to
ZFS.
If I am not mistaken, if you are only using Oracle on the particular Zpol,
Oracle Checksum offers better protection against data corruption.
You can disable ZFS checksums.
Best regards
Mertol
Mertol Ozyoney
Storage Practice - Sales Manager
Sun Microsystems, TR
Istanbul TR
Phone +902123352200
Mobile +905339310752
Fax +902123352222
Email mertol.ozyoney at Sun.COM
-----Original Message-----
From: zfs-discuss-bounces at opensolaris.org
[mailto:zfs-discuss-bounces at opensolaris.org] On Behalf Of Scott Macdonald -
Sun Microsystem
Sent: 01 ?ubat 2008 Cuma 15:31
To: zfs-discuss at opensolaris.org; zfs-interest at sun.com
Subject: [zfs-discuss] Case #65841812
Below is my customers issue. I am stuck on this one. I would appreciate
if someone could help me out on this. Thanks in advance!
ZFS Checksum feature:
I/O checksum is one of the main ZFS features; however, there is also
block checksum done by Oracle. This is
good when utilizing UFS since it does not do checksums, but with ZFS it
can be a waste of CPU time.
Suggestions have been made to change the Oracle db_block_checksum
parameter to false which may give
Significant performance gain on ZFS.
What are Sun''s stance and/or suggestions on making this change on the
ZFS side as well as making the changes on the Oracle side.
--
Scott MacDonald - Sun Support Services
----------------------------------------------------------------------------
----------------------------------------------------------------
_/_/_/_/ _/ _/ _/_/_/ Technical Support Engineer
_/ _/ _/ _/ _/
_/_/ _/ _/ _/ _/ Mon - Fri 8:00am - 4:30pm EST
_/ _/ _/ _/ _/ Ph: 1-800-872-4786 (option 2 & case #)
_/_/_/_/ _/_/_/ _/ _/ email: Scott.M at Sun.com
M I C R O S Y S T E M S alias: s-m at Sun.com
www.sun.com/service/support
----------------------------------------------------------------------------
----------------------------------------------------------------
If you need immediate assistance please call 1-800-USA-4-SUN, option 2
and the case number. If I am unavailable, and you need immediate
assistance, please press 0 for more options.
To track package delivery, call Logistics at 1(800)USA-1SUN, option 1
Thank you for using SUN.
_______________________________________________
zfs-discuss mailing list
zfs-discuss at opensolaris.org
http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
I''m not an Oracle expert but I don''t think Oracle checksumming can correct data. If you have ZFS checksums enabled, and you''re mirroring in your zpools, then ZFS can self-correct as long the checksum on the other half of the mirror is good. Mertol Ozyoney wrote:> Don''t take my words as an expert advice, as I am newbie when it comes to > ZFS. > > If I am not mistaken, if you are only using Oracle on the particular Zpol, > Oracle Checksum offers better protection against data corruption. > You can disable ZFS checksums. > > Best regards > Mertol > > > Mertol Ozyoney > Storage Practice - Sales Manager > > Sun Microsystems, TR > Istanbul TR > Phone +902123352200 > Mobile +905339310752 > Fax +902123352222 > Email mertol.ozyoney at Sun.COM > > > > -----Original Message----- > From: zfs-discuss-bounces at opensolaris.org > [mailto:zfs-discuss-bounces at opensolaris.org] On Behalf Of Scott Macdonald - > Sun Microsystem > Sent: 01 ?ubat 2008 Cuma 15:31 > To: zfs-discuss at opensolaris.org; zfs-interest at sun.com > Subject: [zfs-discuss] Case #65841812 > > Below is my customers issue. I am stuck on this one. I would appreciate > if someone could help me out on this. Thanks in advance! > > > > ZFS Checksum feature: > > I/O checksum is one of the main ZFS features; however, there is also > block checksum done by Oracle. This is > good when utilizing UFS since it does not do checksums, but with ZFS it > can be a waste of CPU time. > Suggestions have been made to change the Oracle db_block_checksum > parameter to false which may give > Significant performance gain on ZFS. > > What are Sun''s stance and/or suggestions on making this change on the > ZFS side as well as making the changes on the Oracle side. > >