Hello list,

what is the quickest way of dumping a DB and restoring it? I have done a

"pg_dump -D database | split --line-bytes 1546m part"

Restoration as

"cat part* | psql database 2> errors 1>/dev/null"

all dumpfiles total about 17Gb. It has been running for 50ish hrs and up
to about the fourth file (5-6 ish Gb) and this is on a raid 5 server.

A while back I did something similar for a table with where I put all
the insert statements in one begin/end/commit block, this slowed down
the restoration process. Will the same problem [slow restoration] occur
if there is no BEGIN and END block? I assume the reason for slow inserts
in this instance is that it allows for rollback, if this is the case
can I turn this off?

Thanks in advance
Eric Lam

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Eric Lam <elam@lisasoft.com> writes:
> what is the quickest way of dumping a DB and restoring it? I have done a

> "pg_dump -D database | split --line-bytes 1546m part"

Don't use "-D" if you want fast restore ...

regards, tom lane

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Tom Lane <tgl@sss.pgh.pa.us> schrieb:

> Eric Lam <elam@lisasoft.com> writes:
> > what is the quickest way of dumping a DB and restoring it? I have done a
>
> > "pg_dump -D database | split --line-bytes 1546m part"
>
> Don't use "-D" if you want fast restore ...

hehe, yes ;-)

http://people.planetpostgresql.org/d...f-pg_dump.html


Andreas
--
Really, I'm not out to destroy Microsoft. That will just be a completely
unintentional side effect. (Linus Torvalds)
"If I was god, I would recompile penguin with --enable-fly." (unknow)
Kaufbach, Saxony, Germany, Europe. N 51.05082°, E 13.56889°

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On Wed, Apr 26, 2006 at 05:14:41PM +0930, Eric Lam wrote:
> all dumpfiles total about 17Gb. It has been running for 50ish hrs and up
> to about the fourth file (5-6 ish Gb) and this is on a raid 5 server.

RAID5 generally doesn't bode too well for performance; that could be
part of the issue.
--
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

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Everyone here always says that RAID 5 isn't good for Postgres. We
have an Apple Xserve RAID configured with RAID 5. We chose RAID 5
because Apple said their Xserve RAID was "optimized" for RAID 5. Not
sure if we made the right decision though. They give an option for
formatting as RAID 0+1. Is that the same as RAID 10 that everyone
talks about? Or is it the reverse?

Thanks,

__________________________________________________ __________________
Brendan Duddridge | CTO | 403-277-5591 x24 | brendan@clickspace.com

ClickSpace Interactive Inc.
Suite L100, 239 - 10th Ave. SE
Calgary, AB T2G 0V9

http://www.clickspace.com

On May 2, 2006, at 11:16 AM, Jim C. Nasby wrote:

> On Wed, Apr 26, 2006 at 05:14:41PM +0930, Eric Lam wrote:
>> all dumpfiles total about 17Gb. It has been running for 50ish hrs
>> and up
>> to about the fourth file (5-6 ish Gb) and this is on a raid 5 server.
>
> RAID5 generally doesn't bode too well for performance; that could be
> part of the issue.
> --
> 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
>
> ---------------------------(end of
> broadcast)---------------------------
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>
> http://archives.postgresql.org
>



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They are not equivalent. As I understand it, RAID 0+1 performs about
the same as RAID 10 when everything is working, but degrades much less
nicely in the presence of a single failed drive, and is more likely to
suffer catastrophic data loss if multiple drives fail.

-- Mark

On Tue, 2006-05-02 at 12:40 -0600, Brendan Duddridge wrote:
> Everyone here always says that RAID 5 isn't good for Postgres. We
> have an Apple Xserve RAID configured with RAID 5. We chose RAID 5
> because Apple said their Xserve RAID was "optimized" for RAID 5. Not
> sure if we made the right decision though. They give an option for
> formatting as RAID 0+1. Is that the same as RAID 10 that everyone
> talks about? Or is it the reverse?
>
> Thanks,
>
> __________________________________________________ __________________
> Brendan Duddridge | CTO | 403-277-5591 x24 | brendan@clickspace.com
>
> ClickSpace Interactive Inc.
> Suite L100, 239 - 10th Ave. SE
> Calgary, AB T2G 0V9
>
> http://www.clickspace.com
>
> On May 2, 2006, at 11:16 AM, Jim C. Nasby wrote:
>
> > On Wed, Apr 26, 2006 at 05:14:41PM +0930, Eric Lam wrote:
> >> all dumpfiles total about 17Gb. It has been running for 50ish hrs
> >> and up
> >> to about the fourth file (5-6 ish Gb) and this is on a raid 5 server.
> >
> > RAID5 generally doesn't bode too well for performance; that could be
> > part of the issue.
> > --
> > 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
> >
> > ---------------------------(end of
> > broadcast)---------------------------
> > TIP 4: Have you searched our list archives?
> >
> > http://archives.postgresql.org
> >
>
>
>
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TIP 6: explain analyze is your friend

RAID 10 is better than RAID 0+1. There is a lot of information on
the net about this, but here is the first one that popped up on
google for me.

http://www.pcguide.com/ref/hdd/perf/...Level01-c.html

The quick summary is that performance is about the same between the
two, but RAID 10 gives better fault tolerance and rebuild
performance. I have seen docs for RAID cards that have confused
these two RAID levels. In addition, some cards claim to support RAID
10, when they actually support RAID 0+1 or even RAID 0+1 with
concatenation (lame, some of the Dell PERCs have this).

RAID 10 with 6 drives would stripe across 3 mirrored pairs. RAID 0+1
with 6 drives is a mirror of two striped arrays (3 disks each). RAID
0+1 (with concatenation) using 6 drives is a mirror of two volumes
(kind of like JBOD) each consisting of 3 drives concatenated together
(it's a cheap implementation, and it gives about the same performance
as RAID 1 but with increased storage capacity and less fault
tolerance). RAID 10 is better than RAID 5 (especially with 6 or less
disks) because you don't have the performance hit for parity (which
dramatically affects rebuild performance and write performance) and
you get better fault tolerance (up to 3 disks can fail in a 6 disk
RAID 10 and you can still be online, with RAID 5 you can only lose 1
drive). All of this comes with a higher cost (more drives and higher
end cards).

-- Will Reese http://blog.rezra.com


On May 2, 2006, at 1:49 PM, Mark Lewis wrote:

> They are not equivalent. As I understand it, RAID 0+1 performs about
> the same as RAID 10 when everything is working, but degrades much less
> nicely in the presence of a single failed drive, and is more likely to
> suffer catastrophic data loss if multiple drives fail.
>
> -- Mark
>
> On Tue, 2006-05-02 at 12:40 -0600, Brendan Duddridge wrote:
>> Everyone here always says that RAID 5 isn't good for Postgres. We
>> have an Apple Xserve RAID configured with RAID 5. We chose RAID 5
>> because Apple said their Xserve RAID was "optimized" for RAID 5. Not
>> sure if we made the right decision though. They give an option for
>> formatting as RAID 0+1. Is that the same as RAID 10 that everyone
>> talks about? Or is it the reverse?
>>
>> Thanks,
>>
>> __________________________________________________ __________________
>> Brendan Duddridge | CTO | 403-277-5591 x24 | brendan@clickspace.com
>>
>> ClickSpace Interactive Inc.
>> Suite L100, 239 - 10th Ave. SE
>> Calgary, AB T2G 0V9
>>
>> http://www.clickspace.com
>>
>> On May 2, 2006, at 11:16 AM, Jim C. Nasby wrote:
>>
>>> On Wed, Apr 26, 2006 at 05:14:41PM +0930, Eric Lam wrote:
>>>> all dumpfiles total about 17Gb. It has been running for 50ish hrs
>>>> and up
>>>> to about the fourth file (5-6 ish Gb) and this is on a raid 5
>>>> server.
>>>
>>> RAID5 generally doesn't bode too well for performance; that could be
>>> part of the issue.
>>> --
>>> 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
>>>
>>> ---------------------------(end of
>>> broadcast)---------------------------
>>> TIP 4: Have you searched our list archives?
>>>
>>> http://archives.postgresql.org
>>>
>>
>>
>>
>> ---------------------------(end of
>> broadcast)---------------------------
>> TIP 9: In versions below 8.0, the planner will ignore your desire to
>> choose an index scan if your joining column's datatypes do not
>> match
>
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TIP 5: don't forget to increase your free space map settings

BTW, you should be able to check to see what the controller is actually
doing by pulling one of the drives from a running array. If it only
hammers 2 drives during the rebuild, it's RAID10. If it hammers all the
drives, it's 0+1.

As for Xserve raid, it is possible to eliminate most (or maybe even all)
of the overhead associated with RAID5, depending on how tricky the
controller wants to be. I believe many large storage appliances actually
use RAID5 internally, but they perform a bunch of 'magic' behind the
scenes to get good performance from it. So, it is possible that the
XServe RAID performs quite well on RAID5. If you provided the results
from bonnie as well as info about the drives I suspect someone here
could tell you if you're getting close to RAID10 performance or not.

On Tue, May 02, 2006 at 02:34:16PM -0500, Will Reese wrote:
> RAID 10 is better than RAID 0+1. There is a lot of information on
> the net about this, but here is the first one that popped up on
> google for me.
>
> http://www.pcguide.com/ref/hdd/perf/...Level01-c.html
>
> The quick summary is that performance is about the same between the
> two, but RAID 10 gives better fault tolerance and rebuild
> performance. I have seen docs for RAID cards that have confused
> these two RAID levels. In addition, some cards claim to support RAID
> 10, when they actually support RAID 0+1 or even RAID 0+1 with
> concatenation (lame, some of the Dell PERCs have this).
>
> RAID 10 with 6 drives would stripe across 3 mirrored pairs. RAID 0+1
> with 6 drives is a mirror of two striped arrays (3 disks each). RAID
> 0+1 (with concatenation) using 6 drives is a mirror of two volumes
> (kind of like JBOD) each consisting of 3 drives concatenated together
> (it's a cheap implementation, and it gives about the same performance
> as RAID 1 but with increased storage capacity and less fault
> tolerance). RAID 10 is better than RAID 5 (especially with 6 or less
> disks) because you don't have the performance hit for parity (which
> dramatically affects rebuild performance and write performance) and
> you get better fault tolerance (up to 3 disks can fail in a 6 disk
> RAID 10 and you can still be online, with RAID 5 you can only lose 1
> drive). All of this comes with a higher cost (more drives and higher
> end cards).
>
> -- Will Reese http://blog.rezra.com
>
>
> On May 2, 2006, at 1:49 PM, Mark Lewis wrote:
>
> >They are not equivalent. As I understand it, RAID 0+1 performs about
> >the same as RAID 10 when everything is working, but degrades much less
> >nicely in the presence of a single failed drive, and is more likely to
> >suffer catastrophic data loss if multiple drives fail.
> >
> >-- Mark
> >
> >On Tue, 2006-05-02 at 12:40 -0600, Brendan Duddridge wrote:
> >>Everyone here always says that RAID 5 isn't good for Postgres. We
> >>have an Apple Xserve RAID configured with RAID 5. We chose RAID 5
> >>because Apple said their Xserve RAID was "optimized" for RAID 5. Not
> >>sure if we made the right decision though. They give an option for
> >>formatting as RAID 0+1. Is that the same as RAID 10 that everyone
> >>talks about? Or is it the reverse?
> >>
> >>Thanks,
> >>
> >>________________________________________________ ____________________
> >>Brendan Duddridge | CTO | 403-277-5591 x24 | brendan@clickspace.com
> >>
> >>ClickSpace Interactive Inc.
> >>Suite L100, 239 - 10th Ave. SE
> >>Calgary, AB T2G 0V9
> >>
> >>http://www.clickspace.com
> >>
> >>On May 2, 2006, at 11:16 AM, Jim C. Nasby wrote:
> >>
> >>>On Wed, Apr 26, 2006 at 05:14:41PM +0930, Eric Lam wrote:
> >>>>all dumpfiles total about 17Gb. It has been running for 50ish hrs
> >>>>and up
> >>>>to about the fourth file (5-6 ish Gb) and this is on a raid 5
> >>>>server.
> >>>
> >>>RAID5 generally doesn't bode too well for performance; that could be
> >>>part of the issue.
> >>>--
> >>>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
> >>>
> >>>---------------------------(end of
> >>>broadcast)---------------------------
> >>>TIP 4: Have you searched our list archives?
> >>>
> >>> http://archives.postgresql.org
> >>>
> >>
> >>
> >>
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> >>broadcast)---------------------------
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> >> choose an index scan if your joining column's datatypes do not
> >> match
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> >---------------------------(end of
> >broadcast)---------------------------
> >TIP 6: explain analyze is your friend
>
>
> ---------------------------(end of broadcast)---------------------------
> TIP 5: don't forget to increase your free space map settings
>

--
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

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match

Hi Jim,

The output from bonnie on my boot drive is:

File './Bonnie.27964', size: 0
Writing with putc()...done
Rewriting...done
Writing intelligently...done
Reading with getc()...done
Reading intelligently...done
Seeker 2...Seeker 1...Seeker 3...start 'em...done...done...done...
-------Sequential Output-------- ---Sequential Input--
--Random--
-Per Char- --Block--- -Rewrite-- -Per Char- --Block---
--Seeks---
Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %
CPU /sec %CPU
0 36325 98.1 66207 22.9 60663 16.2 50553 99.9 710972
100.0 44659.8 191.3


And the output from the RAID drive is:

File './Bonnie.27978', size: 0
Writing with putc()...done
Rewriting...done
Writing intelligently...done
Reading with getc()...done
Reading intelligently...done
Seeker 1...Seeker 2...Seeker 3...start 'em...done...done...done...
-------Sequential Output-------- ---Sequential Input--
--Random--
-Per Char- --Block--- -Rewrite-- -Per Char- --Block---
--Seeks---
Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %
CPU /sec %CPU
0 40365 99.4 211625 61.4 212425 57.0 50740 99.9 730515
100.0 45897.9 190.1


Each drive in the RAID 5 is a 400 GB serial ATA drive. I'm not sure
the manufacturer or the model number as it was all in a packaged box
when we received it and I didn't check.

Do these numbers seem decent enough for a Postgres database?


Thanks,

__________________________________________________ __________________
Brendan Duddridge | CTO | 403-277-5591 x24 | brendan@clickspace.com

ClickSpace Interactive Inc.
Suite L100, 239 - 10th Ave. SE
Calgary, AB T2G 0V9

http://www.clickspace.com

On May 2, 2006, at 3:53 PM, Jim C. Nasby wrote:

> BTW, you should be able to check to see what the controller is
> actually
> doing by pulling one of the drives from a running array. If it only
> hammers 2 drives during the rebuild, it's RAID10. If it hammers all
> the
> drives, it's 0+1.
>
> As for Xserve raid, it is possible to eliminate most (or maybe even
> all)
> of the overhead associated with RAID5, depending on how tricky the
> controller wants to be. I believe many large storage appliances
> actually
> use RAID5 internally, but they perform a bunch of 'magic' behind the
> scenes to get good performance from it. So, it is possible that the
> XServe RAID performs quite well on RAID5. If you provided the results
> from bonnie as well as info about the drives I suspect someone here
> could tell you if you're getting close to RAID10 performance or not.
>
> On Tue, May 02, 2006 at 02:34:16PM -0500, Will Reese wrote:
>> RAID 10 is better than RAID 0+1. There is a lot of information on
>> the net about this, but here is the first one that popped up on
>> google for me.
>>
>> http://www.pcguide.com/ref/hdd/perf/...Level01-c.html
>>
>> The quick summary is that performance is about the same between the
>> two, but RAID 10 gives better fault tolerance and rebuild
>> performance. I have seen docs for RAID cards that have confused
>> these two RAID levels. In addition, some cards claim to support RAID
>> 10, when they actually support RAID 0+1 or even RAID 0+1 with
>> concatenation (lame, some of the Dell PERCs have this).
>>
>> RAID 10 with 6 drives would stripe across 3 mirrored pairs. RAID 0+1
>> with 6 drives is a mirror of two striped arrays (3 disks each). RAID
>> 0+1 (with concatenation) using 6 drives is a mirror of two volumes
>> (kind of like JBOD) each consisting of 3 drives concatenated together
>> (it's a cheap implementation, and it gives about the same performance
>> as RAID 1 but with increased storage capacity and less fault
>> tolerance). RAID 10 is better than RAID 5 (especially with 6 or less
>> disks) because you don't have the performance hit for parity (which
>> dramatically affects rebuild performance and write performance) and
>> you get better fault tolerance (up to 3 disks can fail in a 6 disk
>> RAID 10 and you can still be online, with RAID 5 you can only lose 1
>> drive). All of this comes with a higher cost (more drives and higher
>> end cards).
>>
>> -- Will Reese http://blog.rezra.com
>>
>>
>> On May 2, 2006, at 1:49 PM, Mark Lewis wrote:
>>
>>> They are not equivalent. As I understand it, RAID 0+1 performs
>>> about
>>> the same as RAID 10 when everything is working, but degrades much
>>> less
>>> nicely in the presence of a single failed drive, and is more
>>> likely to
>>> suffer catastrophic data loss if multiple drives fail.
>>>
>>> -- Mark
>>>
>>> On Tue, 2006-05-02 at 12:40 -0600, Brendan Duddridge wrote:
>>>> Everyone here always says that RAID 5 isn't good for Postgres. We
>>>> have an Apple Xserve RAID configured with RAID 5. We chose RAID 5
>>>> because Apple said their Xserve RAID was "optimized" for RAID 5.
>>>> Not
>>>> sure if we made the right decision though. They give an option for
>>>> formatting as RAID 0+1. Is that the same as RAID 10 that everyone
>>>> talks about? Or is it the reverse?
>>>>
>>>> Thanks,
>>>>
>>>> __________________________________________________ _________________
>>>> _
>>>> Brendan Duddridge | CTO | 403-277-5591 x24 |
>>>> brendan@clickspace.com
>>>>
>>>> ClickSpace Interactive Inc.
>>>> Suite L100, 239 - 10th Ave. SE
>>>> Calgary, AB T2G 0V9
>>>>
>>>> http://www.clickspace.com
>>>>
>>>> On May 2, 2006, at 11:16 AM, Jim C. Nasby wrote:
>>>>
>>>>> On Wed, Apr 26, 2006 at 05:14:41PM +0930, Eric Lam wrote:
>>>>>> all dumpfiles total about 17Gb. It has been running for 50ish hrs
>>>>>> and up
>>>>>> to about the fourth file (5-6 ish Gb) and this is on a raid 5
>>>>>> server.
>>>>>
>>>>> RAID5 generally doesn't bode too well for performance; that
>>>>> could be
>>>>> part of the issue.
>>>>> --
>>>>> 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
>>>>>
>>>>> ---------------------------(end of
>>>>> broadcast)---------------------------
>>>>> TIP 4: Have you searched our list archives?
>>>>>
>>>>> http://archives.postgresql.org
>>>>>
>>>>
>>>>
>>>>
>>>> ---------------------------(end of
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>>>> desire to
>>>> choose an index scan if your joining column's datatypes do
>>>> not
>>>> match
>>>
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>>
>>
>> ---------------------------(end of
>> broadcast)---------------------------
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>>
>
> --
> 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
>
> ---------------------------(end of
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> match
>



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Tom Lane wrote:

>Eric Lam <elam@lisasoft.com> writes:
>
>
>>what is the quickest way of dumping a DB and restoring it? I have done a
>>
>>
>
>
>
>> "pg_dump -D database | split --line-bytes 1546m part"
>>
>>
>
>Don't use "-D" if you want fast restore ...
>
> regards, tom lane
>
>
>
thanks, I read that from the doco, the reason why I am using the -D
option is because I was informed by previous people in the company that
they never got a 100% strike rate in database restoration without using
the -D or -d options. If I have enough space on the QA/staging machine
I'll give the no options dump restoration a try.

Anyone have any estimates the time differences between the -D, -d and
[using no option].

regards
Eric Lam

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