Re: [zfs-discuss] zfs send and ARC

2010-03-26 Thread Edward Ned Harvey
In the Thoughts on ZFS Pool Backup Strategies thread it was stated that zfs send, sends uncompress data and uses the ARC. If zfs send sends uncompress data which has already been compress this is not very efficient, and it would be *nice* to see it send the original compress data. (or an

Re: [zfs-discuss] zfs send and ARC

2010-03-26 Thread David Dyer-Bennet
On Fri, March 26, 2010 07:06, Edward Ned Harvey wrote: In the Thoughts on ZFS Pool Backup Strategies thread it was stated that zfs send, sends uncompress data and uses the ARC. If zfs send sends uncompress data which has already been compress this is not very efficient, and it would be

Re: [zfs-discuss] zfs send and ARC

2010-03-26 Thread David Magda
On Fri, March 26, 2010 09:46, David Dyer-Bennet wrote: I don't know that it makes sense to. There are lots of existing filter packages that do compression; so if you want compression, just put them in your pipeline. That way you're not limited by what zfs send has implemented, either. When

[zfs-discuss] zfs send and ARC

2010-03-25 Thread Damon Atkins
In the Thoughts on ZFS Pool Backup Strategies thread it was stated that zfs send, sends uncompress data and uses the ARC. If zfs send sends uncompress data which has already been compress this is not very efficient, and it would be *nice* to see it send the original compress data. (or an

Re: [zfs-discuss] zfs send and ARC

2010-03-25 Thread Richard Elling
On Mar 25, 2010, at 6:13 AM, Damon Atkins wrote: In the Thoughts on ZFS Pool Backup Strategies thread it was stated that zfs send, sends uncompress data and uses the ARC. If zfs send sends uncompress data which has already been compress this is not very efficient, and it would be *nice* to

Re: [zfs-discuss] zfs send and ARC

2010-03-25 Thread Darren J Moffat
Wither it is efficient or not to send the compressed or uncompressed data depends on a lot of factors. If the data is already in the ARC for some other reason then it is likely much more efficient to use that because sending the compressed blocks involves doing IO to disk. Reading the

Re: [zfs-discuss] zfs send and ARC

2010-03-25 Thread Nicolas Williams
On Thu, Mar 25, 2010 at 04:23:38PM +, Darren J Moffat wrote: If the data is in the L2ARC that is still better than going out to the main pool disks to get the compressed version. advocate customer='devil' Well, one could just compress it... If you'd otherwise put compression in the ssh