Re: [zfs-discuss] Enable compression on ZFS root

2008-10-17 Thread Darren J Moffat
dick hoogendijk wrote:
 Vincent Fox wrote:
 
 Or perhaps compression should be the default.
 
 No way please! Things taking even more memory should never be the default.
 An installation switch would be nice though.
 Freedom of coice ;-)

Compression does not take more memory, the data is always uncompressed 
in the in kernel memory ARC anyway.  Data on the L2ARC and ZIL devices 
is always uncompressed.  Compression only impacts what is written to the 
main pool devices.

Compression will use more CPU time, how much depends on which 
compression is choosen.  Note that we already enable compression by 
default for most metadata (ZFS  POSIX layer) (using lzjb), the 
compression flag only impacts application supplied data.

However I don't think compression should be the default setting for ZFS. 
  It may however make sense for it to be explicitly set to on by the 
OpenSolaris installer for datasets that are root/usr/opt filesystems.

I don't want to be burning CPU cycles attempting to compress most of the 
data I store on ZFS because most of it isn't compressible (Audio, Video, 
Image files and OpenDocument files (which are in a ZIP container)).

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Re: [zfs-discuss] Enable compression on ZFS root

2008-10-16 Thread Vincent Fox
 No, the last arguments are not options.nbsp;
 Unfortunately,br
 the syntax doesn't provide a way to specify
 compressionbr
 at the creation time.nbsp; It should, though.nbsp;
 Or perhapsbr
 compression should be the default.br

Should I submit an RFE somewhere then?
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Re: [zfs-discuss] Enable compression on ZFS root

2008-10-16 Thread dick hoogendijk

Vincent Fox wrote:

 Or perhaps compression should be the default.

No way please! Things taking even more memory should never be the default.
An installation switch would be nice though.
Freedom of coice ;-)

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Dick Hoogendijk -- PGP/GnuPG key: F86289CE
++ http://nagual.nl/ | SunOS 10u5 05/08 ++

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[zfs-discuss] Enable compression on ZFS root

2008-10-15 Thread Vincent Fox
Does it seem feasible/reasonable to enable compression on ZFS root disks during 
JumpStart?

Seems like it could buy some space  performance.
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Re: [zfs-discuss] Enable compression on ZFS root

2008-10-15 Thread Cyril Plisko
On Thu, Oct 16, 2008 at 12:24 AM, Vincent Fox [EMAIL PROTECTED] wrote:
 Does it seem feasible/reasonable to enable compression on ZFS root disks 
 during JumpStart?

Absolutely. I did it (compression=on) on all my machines - ranged from
laptop to servers. Beware, though, that on oldish CPU it can incur
noticeble CPU overhead. Oh, and don't use gzip compression - it won't
boot.

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Re: [zfs-discuss] Enable compression on ZFS root

2008-10-15 Thread Richard Elling
Vincent Fox wrote:
 Does it seem feasible/reasonable to enable compression on ZFS root disks 
 during JumpStart?

 Seems like it could buy some space  performance.
   

Yes.  There have been several people who do this regularly.
Glenn wrote a blog on how to do this when installing OpenSolaris 2008.05
http://blogs.sun.com/glagasse/entry/howto_enable_zfs_compression_when

I haven't used JumpStart in some time, but it appears as though the last
arguments of the pool keyword are passed to zpool create, so you should
be able to set the parameters there.  Cindy?
 -- richard

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Re: [zfs-discuss] Enable compression on ZFS root

2008-10-15 Thread Vincent Fox
Did you enable it in the jumpstart profile somehow?

If you do it after install the OS files are not compressed.
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Re: [zfs-discuss] Enable compression on ZFS root

2008-10-15 Thread Lori Alt

Richard Elling wrote:

Vincent Fox wrote:
  

Does it seem feasible/reasonable to enable compression on ZFS root disks during 
JumpStart?

Seems like it could buy some space  performance.
  



Yes.  There have been several people who do this regularly.
Glenn wrote a blog on how to do this when installing OpenSolaris 2008.05
http://blogs.sun.com/glagasse/entry/howto_enable_zfs_compression_when

I haven't used JumpStart in some time, but it appears as though the last
arguments of the pool keyword are passed to zpool create, so you should
be able to set the parameters there.  Cindy?
  

No, the last arguments are not options.  Unfortunately,
the syntax doesn't provide a way to specify compression
at the creation time.  It should, though.  Or perhaps
compression should be the default.

lori



 -- richard

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