Re: [zfs-discuss] L2ARC, block based or file based?

2012-01-13 Thread Marion Hakanson
mattba...@gmail.com said: > We're looking at buying some additional SSD's for L2ARC (as well as > additional RAM to support the increased L2ARC size) and I'm wondering if we > NEED to plan for them to be large enough to hold the entire file or if ZFS > can cache the most heavily used parts of a sin

[zfs-discuss] L2ARC, block based or file based?

2012-01-13 Thread Matt Banks
I'm sorry to be asking such a basic question that would seem to be easily found on Google, but after 30 minutes of "googling" and looking through this lists' archives, I haven't found a definitive answer. Is the L2ARC caching scheme based on files or blocks? The reason I ask: We have several da

Re: [zfs-discuss] zfs defragmentation via resilvering?

2012-01-13 Thread Bob Friesenhahn
On Thu, 12 Jan 2012, Edward Ned Harvey wrote: Suppose you have a 1G file open, and a snapshot of this file is on disk from a previous point in time. for ( i=0 ; i<1trillion ; i++ ) { seek(random integer in range[0 to 1G]); write(4k); } Something like this would quickly try to wri

Re: [zfs-discuss] Injection of ZFS snapshots into existing data, and replacement of older snapshots with zfs recv without truncating newer ones

2012-01-13 Thread Edward Ned Harvey
> From: zfs-discuss-boun...@opensolaris.org [mailto:zfs-discuss- > boun...@opensolaris.org] On Behalf Of Jim Klimov > > Perhaps I need to specify some usecases more clearly: Actually, I'm not sure you do need to specify usecases more clearly - Because the idea is obviously awesome. The main prob