DOC: Wal update

Zdenek Kotala wrote:

I add few sentences how to write cache works on Solaris platform.

I have updated our documentation with the attached patch. I was able to
verify all the information in this change.

I changed your original wording because the statement that UFS turns off
write cache seemed unclear because the file system seems independent of
the disk write cache. (What happens if you have UFS and ZFS on the same
drive?)

Anyway I think the attached wording is fine.

--
Bruce Momjian <bruce@momjian.us> http://momjian.us
EnterpriseDB http://postgres.enterprisedb.com

+ If your life is a hard drive, Christ can be your backup. +

Bruce Momjian wrote:

Zdenek Kotala wrote:

I add few sentences how to write cache works on Solaris platform.

I have updated our documentation with the attached patch. I was able to
verify all the information in this change.

Thanks.

I changed your original wording because the statement that UFS turns off
write cache seemed unclear because the file system seems independent of
the disk write cache. (What happens if you have UFS and ZFS on the same
drive?)

You are right UFS does not modify (write) cache setting and it is usually
disabled by default on most disks. If ZFS and UFS are on same disk, than ZFS
don't enable disk cache. It is a reason why put ZFS on separate disk is better. See
http://www.solarisinternals.com/wiki/index.php/ZFS_Best_Practices_Guide#Storage_Pools

Anyway I think the attached wording is fine.

Yes, it is.

Zdenek

PS: There are some articles about ZFS.

http://www.solarisinternals.com/wiki/index.php/ZFS_Best_Practices_Guide
http://www.solarisinternals.com/wiki/index.php/ZFS_Evil_Tuning_Guide
http://www.solarisinternals.com/wiki/index.php/ZFS_for_Databases

Zdenek Kotala wrote:

Bruce Momjian wrote:

Zdenek Kotala wrote:

I add few sentences how to write cache works on Solaris platform.

I have updated our documentation with the attached patch. I was able to
verify all the information in this change.

Thanks.

I changed your original wording because the statement that UFS turns off
write cache seemed unclear because the file system seems independent of
the disk write cache. (What happens if you have UFS and ZFS on the same
drive?)

You are right UFS does not modify (write) cache setting and it is usually
disabled by default on most disks. If ZFS and UFS are on same disk, than ZFS
don't enable disk cache. It is a reason why put ZFS on separate disk is better. See
http://www.solarisinternals.com/wiki/index.php/ZFS_Best_Practices_Guide#Storage_Pools

Anyway I think the attached wording is fine.

Yes, it is.

Zdenek

PS: There are some articles about ZFS.

http://www.solarisinternals.com/wiki/index.php/ZFS_Best_Practices_Guide
http://www.solarisinternals.com/wiki/index.php/ZFS_Evil_Tuning_Guide
http://www.solarisinternals.com/wiki/index.php/ZFS_for_Databases

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--
Bruce Momjian <bruce@momjian.us> http://momjian.us
EnterpriseDB http://postgres.enterprisedb.com

+ If your life is a hard drive, Christ can be your backup. +