Re: What to do about snapshot-aware defrag

2014-06-04 Thread Chris Murphy
On Jun 4, 2014, at 7:15 AM, Martin wrote: > > Consider using noatime as a /default/ being as there are no known > 'must-use' use cases. The quote I'm finding on the interwebs is POSIX “requires that operating systems maintain file system metadata that records when each file was last accessed

Re: What to do about snapshot-aware defrag

2014-06-04 Thread Martin
On 04/06/14 10:19, Erkki Seppala wrote: > Martin writes: > >> The *ONLY* application that I know of that uses atime is Mutt and then >> *only* for mbox files!... > > However, users, such as myself :), can be interested in when a certain > file has been last accessed. With snapshots I can even ge

Re: What to do about snapshot-aware defrag

2014-06-04 Thread Erkki Seppala
Martin writes: > The *ONLY* application that I know of that uses atime is Mutt and then > *only* for mbox files!... However, users, such as myself :), can be interested in when a certain file has been last accessed. With snapshots I can even get an idea of all the times the file has been accesse

Re: What to do about snapshot-aware defrag

2014-06-03 Thread Martin
On 02/06/14 14:22, Josef Bacik wrote: > On 05/30/2014 06:00 PM, Martin wrote: >> OK... I'll jump in... >> >> On 30/05/14 21:43, Josef Bacik wrote: >>> Hello, >>> >>> TL;DR: I want to only do snapshot-aware defrag on inodes in snapshots >>> that haven't changed since the snapshot was taken. Yay or

Re: What to do about snapshot-aware defrag

2014-06-02 Thread Josef Bacik
On 05/30/2014 06:00 PM, Martin wrote: OK... I'll jump in... On 30/05/14 21:43, Josef Bacik wrote: Hello, TL;DR: I want to only do snapshot-aware defrag on inodes in snapshots that haven't changed since the snapshot was taken. Yay or nay (with a reason why for nay) [...] === Summary and wh

Re: What to do about snapshot-aware defrag

2014-06-02 Thread Josef Bacik
On 06/01/2014 11:07 PM, Mitch Harder wrote: On Sat, May 31, 2014 at 6:51 PM, Brendan Hide wrote: On 2014/05/31 12:00 AM, Martin wrote: OK... I'll jump in... On 30/05/14 21:43, Josef Bacik wrote: [snip] Option 1: Only relink inodes that haven't changed since the snapshot was taken. Pros:

Re: What to do about snapshot-aware defrag

2014-06-01 Thread Mitch Harder
On Sat, May 31, 2014 at 6:51 PM, Brendan Hide wrote: > On 2014/05/31 12:00 AM, Martin wrote: >> >> OK... I'll jump in... >> >> On 30/05/14 21:43, Josef Bacik wrote: >>> >>> [snip] >>> >>> Option 1: Only relink inodes that haven't changed since the snapshot was >>> taken. >>> >>> Pros: >>> -Faster

Re: What to do about snapshot-aware defrag

2014-05-31 Thread Duncan
Brendan Hide posted on Sun, 01 Jun 2014 01:51:49 +0200 as excerpted: >> Will option one mean that we always need to mount with noatime or >> read-only to allow snapshot defragging to do anything? > > That is a very good question. I very rarely have mounts without noatime > - and usually only beca

Re: What to do about snapshot-aware defrag

2014-05-31 Thread Brendan Hide
On 2014/05/31 12:00 AM, Martin wrote: OK... I'll jump in... On 30/05/14 21:43, Josef Bacik wrote: [snip] Option 1: Only relink inodes that haven't changed since the snapshot was taken. Pros: -Faster -Simpler -Less duplicated code, uses existing functions for tricky operations so less likely to

Re: What to do about snapshot-aware defrag

2014-05-30 Thread Martin
OK... I'll jump in... On 30/05/14 21:43, Josef Bacik wrote: > Hello, > > TL;DR: I want to only do snapshot-aware defrag on inodes in snapshots > that haven't changed since the snapshot was taken. Yay or nay (with a > reason why for nay) [...] > > === Summary and what I need === > > Option 1:

What to do about snapshot-aware defrag

2014-05-30 Thread Josef Bacik
Hello, TL;DR: I want to only do snapshot-aware defrag on inodes in snapshots that haven't changed since the snapshot was taken. Yay or nay (with a reason why for nay) === How snapshot aware defrag currently works === First the defrag stuff will go through and read in and mark dirty a big a