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* freebsd/softupdates for data dir
@ 2006-04-04 00:58 Miguel <mmiranda@123.com.sv>
2006-04-04 02:10 ` Re: freebsd/softupdates for data dir Mark Kirkwood <markir@paradise.net.nz>
0 siblings, 1 reply; 6+ messages in thread
From: Miguel @ 2006-04-04 00:58 UTC (permalink / raw)
To: pgsql-performance
Hi, reading the archives i cant find a clear answer about softupdates in
freebsd, is it recommended to enable it for the data directory?
---
miguel
^ permalink raw reply [nested|flat] 6+ messages in thread
* Re: freebsd/softupdates for data dir
2006-04-04 00:58 freebsd/softupdates for data dir Miguel <mmiranda@123.com.sv>
@ 2006-04-04 02:10 ` Mark Kirkwood <markir@paradise.net.nz>
2006-04-04 14:41 ` Re: freebsd/softupdates for data dir Vivek Khera <vivek@khera.org>
0 siblings, 1 reply; 6+ messages in thread
From: Mark Kirkwood @ 2006-04-04 02:10 UTC (permalink / raw)
To: Miguel <mmiranda@123.com.sv>; +Cc: pgsql-performance
Miguel wrote:
> Hi, reading the archives i cant find a clear answer about softupdates in
> freebsd, is it recommended to enable it for the data directory?
>
There is a pretty good article about softupdates and journelling here:
http://www.usenix.org/publications/library/proceedings/usenix2000/general/full_papers/seltzer/seltze...
and in the freebsd docs here:
http://www.freebsd.org/doc/handbook/configtuning-disk.html
Postgres does not do a lot of file meta-data operations (unless you do a
*lot* of CREATE/DROP INDEX/TABLE/DATABASE), so the performance gains
associated with softupdates will probably be minimal.
I've always left them on, and never had any issues...(even after
unscheduled power loss - which happened here yesterday). As I understand
it, the softupdate code reorders *metadata* operations, and does not
alter data operations - so the effect of fysnc(2) on a preexisting file
is not changed by softupdates being on or off.
Cheers
Mark
^ permalink raw reply [nested|flat] 6+ messages in thread
* Re: freebsd/softupdates for data dir
2006-04-04 00:58 freebsd/softupdates for data dir Miguel <mmiranda@123.com.sv>
2006-04-04 02:10 ` Re: freebsd/softupdates for data dir Mark Kirkwood <markir@paradise.net.nz>
@ 2006-04-04 14:41 ` Vivek Khera <vivek@khera.org>
2006-04-05 22:07 ` Re: freebsd/softupdates for data dir Jim Nasby <jnasby@pervasive.com>
0 siblings, 1 reply; 6+ messages in thread
From: Vivek Khera @ 2006-04-04 14:41 UTC (permalink / raw)
To: pgsql-performance
On Apr 3, 2006, at 10:10 PM, Mark Kirkwood wrote:
> I've always left them on, and never had any issues...(even after
> unscheduled power loss - which happened here yesterday). As I
> understand it, the softupdate code reorders *metadata* operations,
> and does not alter data operations - so the effect of fysnc(2) on a
> preexisting file is not changed by softupdates being on or off.
This is also my understanding, and I also leave softupdates on for
the data partition. Even if it doesn't improve performance, it will
not reduce it, and otherwise does no harm with respect to postgres'
disk usage.
^ permalink raw reply [nested|flat] 6+ messages in thread
* Re: freebsd/softupdates for data dir
2006-04-04 00:58 freebsd/softupdates for data dir Miguel <mmiranda@123.com.sv>
2006-04-04 02:10 ` Re: freebsd/softupdates for data dir Mark Kirkwood <markir@paradise.net.nz>
2006-04-04 14:41 ` Re: freebsd/softupdates for data dir Vivek Khera <vivek@khera.org>
@ 2006-04-05 22:07 ` Jim Nasby <jnasby@pervasive.com>
2006-04-06 13:45 ` Re: freebsd/softupdates for data dir Vivek Khera <vivek@khera.org>
0 siblings, 1 reply; 6+ messages in thread
From: Jim Nasby @ 2006-04-05 22:07 UTC (permalink / raw)
To: Vivek Khera <vivek@khera.org>; +Cc: pgsql-performance
On Apr 4, 2006, at 10:41 AM, Vivek Khera wrote:
> On Apr 3, 2006, at 10:10 PM, Mark Kirkwood wrote:
>
>> I've always left them on, and never had any issues...(even after
>> unscheduled power loss - which happened here yesterday). As I
>> understand it, the softupdate code reorders *metadata* operations,
>> and does not alter data operations - so the effect of fysnc(2) on
>> a preexisting file is not changed by softupdates being on or off.
>
> This is also my understanding, and I also leave softupdates on for
> the data partition. Even if it doesn't improve performance, it
> will not reduce it, and otherwise does no harm with respect to
> postgres' disk usage.
More importantly, it allows the system to come up and do fsck in the
background. If you've got a large database that's a pretty big benefit.
--
Jim C. Nasby, Sr. Engineering Consultant jnasby@pervasive.com
Pervasive Software http://pervasive.com work: 512-231-6117
vcard: http://jim.nasby.net/pervasive.vcf cell: 512-569-9461
^ permalink raw reply [nested|flat] 6+ messages in thread
* Re: freebsd/softupdates for data dir
2006-04-04 00:58 freebsd/softupdates for data dir Miguel <mmiranda@123.com.sv>
2006-04-04 02:10 ` Re: freebsd/softupdates for data dir Mark Kirkwood <markir@paradise.net.nz>
2006-04-04 14:41 ` Re: freebsd/softupdates for data dir Vivek Khera <vivek@khera.org>
2006-04-05 22:07 ` Re: freebsd/softupdates for data dir Jim Nasby <jnasby@pervasive.com>
@ 2006-04-06 13:45 ` Vivek Khera <vivek@khera.org>
2006-04-11 22:59 ` Re: freebsd/softupdates for data dir Jim C. Nasby <jnasby@pervasive.com>
0 siblings, 1 reply; 6+ messages in thread
From: Vivek Khera @ 2006-04-06 13:45 UTC (permalink / raw)
To: pgsql-performance
On Apr 5, 2006, at 6:07 PM, Jim Nasby wrote:
>
> More importantly, it allows the system to come up and do fsck in
> the background. If you've got a large database that's a pretty big
> benefit.
That's a UFS2 feature, not a soft-updates feature.
^ permalink raw reply [nested|flat] 6+ messages in thread
* Re: freebsd/softupdates for data dir
2006-04-04 00:58 freebsd/softupdates for data dir Miguel <mmiranda@123.com.sv>
2006-04-04 02:10 ` Re: freebsd/softupdates for data dir Mark Kirkwood <markir@paradise.net.nz>
2006-04-04 14:41 ` Re: freebsd/softupdates for data dir Vivek Khera <vivek@khera.org>
2006-04-05 22:07 ` Re: freebsd/softupdates for data dir Jim Nasby <jnasby@pervasive.com>
2006-04-06 13:45 ` Re: freebsd/softupdates for data dir Vivek Khera <vivek@khera.org>
@ 2006-04-11 22:59 ` Jim C. Nasby <jnasby@pervasive.com>
0 siblings, 0 replies; 6+ messages in thread
From: Jim C. Nasby @ 2006-04-11 22:59 UTC (permalink / raw)
To: Vivek Khera <vivek@khera.org>; +Cc: pgsql-performance
On Thu, Apr 06, 2006 at 09:45:34AM -0400, Vivek Khera wrote:
>
> On Apr 5, 2006, at 6:07 PM, Jim Nasby wrote:
>
> >
> >More importantly, it allows the system to come up and do fsck in
> >the background. If you've got a large database that's a pretty big
> >benefit.
>
> That's a UFS2 feature, not a soft-updates feature.
It's both. You can't background fsck with softupdates disabled.
--
Jim C. Nasby, Sr. Engineering Consultant jnasby@pervasive.com
Pervasive Software http://pervasive.com work: 512-231-6117
vcard: http://jim.nasby.net/pervasive.vcf cell: 512-569-9461
^ permalink raw reply [nested|flat] 6+ messages in thread
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-- links below jump to the message on this page --
2006-04-04 00:58 freebsd/softupdates for data dir Miguel <mmiranda@123.com.sv>
2006-04-04 02:10 ` Mark Kirkwood <markir@paradise.net.nz>
2006-04-04 14:41 ` Vivek Khera <vivek@khera.org>
2006-04-05 22:07 ` Jim Nasby <jnasby@pervasive.com>
2006-04-06 13:45 ` Vivek Khera <vivek@khera.org>
2006-04-11 22:59 ` Jim C. Nasby <jnasby@pervasive.com>
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