Time Machine is a Resource Hog
in [Mac Applications]
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From: Steven Fisher on 13 Mar 2010 02:50 In article <1jf8wg5.g4f4zi42nhzhN%jamiekg(a)wizardling.geek.nz>, jamiekg(a)wizardling.geek.nz (Jamie Kahn Genet) wrote: > No, but it makes sense for a background task to be well behaved. TM is > an utter I/O hog. No testing... *sigh* If it was that bad, and certainly if it had no testing, you would have fewer people disagreeing with you. Steve
From: Jamie Kahn Genet on 13 Mar 2010 04:55 Steven Fisher <sdfisher(a)spamcop.net> wrote: > In article <1jf8wg5.g4f4zi42nhzhN%jamiekg(a)wizardling.geek.nz>, > jamiekg(a)wizardling.geek.nz (Jamie Kahn Genet) wrote: > > > No, but it makes sense for a background task to be well behaved. TM is > > an utter I/O hog. No testing... *sigh* > > If it was that bad, and certainly if it had no testing, you would have > fewer people disagreeing with you. > > > Steve And fewer people on the Apple boards. -- If you're not part of the solution, you're part of the precipitate.
From: Tom Harrington on 13 Mar 2010 15:57 In article <4b9b10f0$0$22125$742ec2ed(a)news.sonic.net>, Kevin McMurtrie <mcmurtrie(a)pixelmemory.us> wrote: > In article <tph-3CDE97.15591012032010(a)localhost>, > Tom Harrington <tph(a)pcisys.no.spam.dammit.net> wrote: > > > In article <4b9a7c01$0$22099$742ec2ed(a)news.sonic.net>, > > Kevin McMurtrie <mcmurtrie(a)pixelmemory.us> wrote: > > > > > The crazy slowness for a small backup is mostly the interaction with > > > Mail.app. TM subscribes to a list of changes on the filesystem but > > > these messages are for directories only. Every time you get new mail, > > > TM notices that the 'Messages' directory has changed. TM must then > > > compare metadata between the backup and local mail folder for each file. > > > For an older mail account it could be scanning tens of thousands or > > > hundreds of thousands of files just to get your last few e-mails > > > archived. > > > > Is this documented anywhere? I've heard it a couple of times but I'm > > not sure what the basis is. Given how fsevents works, it seems entirely > > plausible, but I still wonder if there's any official comment on it. > > > > I only ask because I have about 60 zillion old emails, and my TM backups > > take a while, but before I make major changes to my workflow I'd like to > > be sure the changes actually make sense. > > I was running "fs_usage" to see what it was so busy fussing with. You > can run this as root or admin on a command line: > > fs_usage backupd > > You'll see every file operation for the Time Machine daemon. Thanks, that's an excellent idea. -- Tom "Tom" Harrington Independent Mac OS X developer since 2002 http://www.atomicbird.com/
From: Tom Harrington on 13 Mar 2010 17:24
In article <tph-BC0278.13574913032010(a)localhost>, Tom Harrington <tph(a)pcisys.no.spam.dammit.net> wrote: > In article <4b9b10f0$0$22125$742ec2ed(a)news.sonic.net>, > Kevin McMurtrie <mcmurtrie(a)pixelmemory.us> wrote: > > > In article <tph-3CDE97.15591012032010(a)localhost>, > > Tom Harrington <tph(a)pcisys.no.spam.dammit.net> wrote: > > > > > In article <4b9a7c01$0$22099$742ec2ed(a)news.sonic.net>, > > > Kevin McMurtrie <mcmurtrie(a)pixelmemory.us> wrote: > > > > > > > The crazy slowness for a small backup is mostly the interaction with > > > > Mail.app. TM subscribes to a list of changes on the filesystem but > > > > these messages are for directories only. Every time you get new mail, > > > > TM notices that the 'Messages' directory has changed. TM must then > > > > compare metadata between the backup and local mail folder for each > > > > file. > > > > For an older mail account it could be scanning tens of thousands or > > > > hundreds of thousands of files just to get your last few e-mails > > > > archived. > > > > > > Is this documented anywhere? I've heard it a couple of times but I'm > > > not sure what the basis is. Given how fsevents works, it seems entirely > > > plausible, but I still wonder if there's any official comment on it. > > > > > > I only ask because I have about 60 zillion old emails, and my TM backups > > > take a while, but before I make major changes to my workflow I'd like to > > > be sure the changes actually make sense. > > > > I was running "fs_usage" to see what it was so busy fussing with. You > > can run this as root or admin on a command line: > > > > fs_usage backupd > > > > You'll see every file operation for the Time Machine daemon. > > Thanks, that's an excellent idea. Trying this confirmed Mail's role in this. I'm still working on what I can/should do about it, because it also indicates Mail has been having some severe problems that aren't apparent in the UI and that can't be fixed just by changing my behavior. But that's a topic for a different post, I think. -- Tom "Tom" Harrington Independent Mac OS X developer since 2002 http://www.atomicbird.com/ |