Re: back up to disk

Re: back up to disk

[JP Howard]

On Wed, 16 Oct 2002 05:15:33 +0400, "Hans Reiser" <reiser@namesys.com>
said:
> JP Howard wrote:
> 
> >We've been thinking about something like that, using this extremely nifty
> >trick:
> >
> >http://www.mikerubel.org/computers/rsync_snapshots/
> >
> This is brilliantly simple.
> 
I thought so too. I'm cc'ing the author so he can bask in the glory...
;-)
> >
> >Back in the old days (i.e. last week) when we were planning around Ext3,
> >we were thinking of combining it with this product:
> >
> >http://www.shaolinmicro.com/product/cogofs/index.php
> >
> This looks reasonable as a product, and not unreasonably expensive for 
> servers.   There are some advantages to tight integration though, in 
> that you can compress at flush time.
> 
Yes indeed. And I haven't seen this product used anywhere--I don't know
how reliable it is. It's binary-only, which I don't like, and you have to
get a version for your particular kernel (and really, who uses stock
kernels?...)
> >
> >The two combined, with ATA RAID, provide fast, redundent, incremental,
> >compressed backups.
> >
> >Does ReiserFS support transparent compression?
> >
> This is one of the features that won't make the Halloween deadline, but 
> might be slipped in later.
> 
> If not, are there any
> >plans in this direction? Benchmarks I've seen in the past suggest that
> >compressed file systems generally improve performance (especially when
> >using something fast like LZOP) since CPUs are so fast--and of course for
> >backups being able to store more on fewer disks is nice...
> >
> What I had heard was that they generally slowed peformance, but maybe my 
> info is old.
> 
> CPUs are faster now, and maybe compression algorithms are faster.
> 
> Can you give more details?
> 
I'm just passing on anecdotal information, I'm afraid. I can tell you
that LZOP is *seriously* fast. 
  http://www.oberhumer.com/opensource/lzop/

Every benchmark I've seen shows it #1 for speed. We see around 50%
compression ratio on our Cyrus mail store using LZOP compression on our
backups.

It's easy enough to construct some simple benchmarks like this:
----
# time zgrep foobar maillog.1.gz
real    0m6.924s
user    0m3.140s
sys     0m0.620s

# time grep foobar maillog.1

real    0m19.972s
user    0m0.290s
sys     0m0.620s
----

Of course, it depends a lot on the CPU and HDD configuration, and where
your system is loaded. We always find our IMAP and SMTP servers IO bound,
with plenty of CPU free. It's very expensive to change from a 5x73GB to a
10x36GB config, so buying more IO performance is an expensive
proposition.

Re: back up to disk

[Edward Shishkin]

JP Howard wrote:
> 
> On Wed, 16 Oct 2002 05:15:33 +0400, "Hans Reiser" <reiser@namesys.com>
> said:
> > JP Howard wrote:
> >
> > >We've been thinking about something like that, using this extremely nifty
> > >trick:
> > >
> > >http://www.mikerubel.org/computers/rsync_snapshots/
> > >
> > This is brilliantly simple.
> >
> I thought so too. I'm cc'ing the author so he can bask in the glory...
> ;-)
> > >
> > >Back in the old days (i.e. last week) when we were planning around Ext3,
> > >we were thinking of combining it with this product:
> > >
> > >http://www.shaolinmicro.com/product/cogofs/index.php
> > >
> > This looks reasonable as a product, and not unreasonably expensive for
> > servers.   There are some advantages to tight integration though, in
> > that you can compress at flush time.
> >
> Yes indeed. And I haven't seen this product used anywhere--I don't know
> how reliable it is. It's binary-only, which I don't like, and you have to
> get a version for your particular kernel (and really, who uses stock
> kernels?...)
> > >
> > >The two combined, with ATA RAID, provide fast, redundent, incremental,
> > >compressed backups.
> > >
> > >Does ReiserFS support transparent compression?
> > >
> > This is one of the features that won't make the Halloween deadline, but
> > might be slipped in later.
> >
> > If not, are there any
> > >plans in this direction? Benchmarks I've seen in the past suggest that
> > >compressed file systems generally improve performance (especially when
> > >using something fast like LZOP) since CPUs are so fast--and of course for
> > >backups being able to store more on fewer disks is nice...
> > >
> > What I had heard was that they generally slowed peformance, but maybe my
> > info is old.
> >
> > CPUs are faster now, and maybe compression algorithms are faster.
> >
> > Can you give more details?
> >
> I'm just passing on anecdotal information, I'm afraid. I can tell you
> that LZOP is *seriously* fast.
>   http://www.oberhumer.com/opensource/lzop/
> 
> Every benchmark I've seen shows it #1 for speed. We see around 50%
> compression ratio on our Cyrus mail store using LZOP compression on our
> backups.

It looks fine, although I expect that file system will produce lower
compression ratio since we can not use too large cluster size as this
algorithm does (256K).

Edward.   

> 
> It's easy enough to construct some simple benchmarks like this:
> ----
> # time zgrep foobar maillog.1.gz
> real    0m6.924s
> user    0m3.140s
> sys     0m0.620s
> 
> # time grep foobar maillog.1
> 
> real    0m19.972s
> user    0m0.290s
> sys     0m0.620s
> ----
> 
> Of course, it depends a lot on the CPU and HDD configuration, and where
> your system is loaded. We always find our IMAP and SMTP servers IO bound,
> with plenty of CPU free. It's very expensive to change from a 5x73GB to a
> 10x36GB config, so buying more IO performance is an expensive
> proposition.

Re: back up to disk

[JP Howard]

On Tue, 15 Oct 2002 23:05:44 +0200, "Russell Coker"
<bofh@coker.com.au> said:
> Here's an interesting article I just read.  It's just a device with a
> bunch of ATA drives inside, up to 2T of storage.  Probably anyone here
> could produce something based on ReiserFS to compete with it...
>
> Storage start-up Avamar Technologies is launching an appliance this
> week that it claims backs up network data more quickly and less
> expensively than tape.
> http://www.nwfusion.com/news/2002/1014avamar.html?net
>
We've been thinking about something like that, using this extremely nifty
trick:

http://www.mikerubel.org/computers/rsync_snapshots/

Back in the old days (i.e. last week) when we were planning around Ext3,
we were thinking of combining it with this product:

http://www.shaolinmicro.com/product/cogofs/index.php

The two combined, with ATA RAID, provide fast, redundent, incremental,
compressed backups.

Does ReiserFS support transparent compression? If not, are there any
plans in this direction? Benchmarks I've seen in the past suggest that
compressed file systems generally improve performance (especially when
using something fast like LZOP) since CPUs are so fast--and of course for
backups being able to store more on fewer disks is nice...

Off-topic: anyone know of good vendors offering rackmount servers with
room for lots of IDE drives? Looking at Dell, IBM, and Compaq they all
use exclusively SCSI in there 2U rackmount servers.

Re: back up to disk

[Hans Reiser]

JP Howard wrote:

>We've been thinking about something like that, using this extremely nifty
>trick:
>
>http://www.mikerubel.org/computers/rsync_snapshots/
>
This is brilliantly simple.

>
>Back in the old days (i.e. last week) when we were planning around Ext3,
>we were thinking of combining it with this product:
>
>http://www.shaolinmicro.com/product/cogofs/index.php
>
This looks reasonable as a product, and not unreasonably expensive for 
servers.   There are some advantages to tight integration though, in 
that you can compress at flush time.

>
>The two combined, with ATA RAID, provide fast, redundent, incremental,
>compressed backups.
>
>Does ReiserFS support transparent compression?
>
This is one of the features that won't make the Halloween deadline, but 
might be slipped in later.

> If not, are there any
>plans in this direction? Benchmarks I've seen in the past suggest that
>compressed file systems generally improve performance (especially when
>using something fast like LZOP) since CPUs are so fast--and of course for
>backups being able to store more on fewer disks is nice...
>
What I had heard was that they generally slowed peformance, but maybe my 
info is old.

CPUs are faster now, and maybe compression algorithms are faster.

Can you give more details?

Re: back up to disk

[Valdis.Kletnieks]

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On Wed, 16 Oct 2002 05:15:33 +0400, Hans Reiser said:

> What I had heard was that they generally slowed peformance, but maybe my 
> info is old.

Even back in the days when an IBM RS6000-220 (66mz 601 chipset) was a "new"
machine, I found it actually gave a 20-30% total throughput boost, because
even if the CPU wasn't blazing fast, it was faster to read 3-5 512 byte
blocks off the disk and decompress them to get a 4K filesystem block than
it was to actually read all 8 512-byte blocks.  Among other things, you
get back half your disk throughput, so you can sustain twice the I/Os....
-- 
				Valdis Kletnieks
				Computer Systems Senior Engineer
				Virginia Tech


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Re: back up to disk

[Toby Dickenson]

On Tuesday 15 Oct 2002 11:42 pm, JP Howard wrote:

> We've been thinking about something like that, using this extremely nifty
> trick:
>
> http://www.mikerubel.org/computers/rsync_snapshots/

One limitation with any scheme based on rsync is that it uses memory 
proportional to the number of files. This may or may not be a problem for 
you.

RE: back up to disk

[Bingner Sam J Contractor CAF CSS/SCHE]

can anybody say SAN?

SAN:  Acronym: Storage Area Network

This looks like it is just a SAN, and a little software to show when the
same data is written twice and reference the first instance instead of
writing it again...  I suspect it could use any filesystem on the drives you
wanted...

	Sam Bingner
	PACAF CSS/SCHE

-----Original Message-----
From: Russell Coker [mailto:bofh@coker.com.au]
Sent: Tuesday, October 15, 2002 11:06 AM
To: ReiserFS
Subject: [reiserfs-list] back up to disk


Here's an interesting article I just read.  It's just a device with a bunch
of 
ATA drives inside, up to 2T of storage.  Probably anyone here could produce 
something based on ReiserFS to compete with it...


Storage start-up Avamar Technologies is launching an appliance 
this week that it claims backs up network data more quickly and 
less expensively than tape. 
http://www.nwfusion.com/news/2002/1014avamar.html?net

-- 
http://www.coker.com.au/bonnie++/     Bonnie++ hard drive benchmark
http://www.coker.com.au/postal/       Postal SMTP/POP benchmark
http://www.coker.com.au/projects.html Projects I am working on
http://www.coker.com.au/~russell/     My home page

back up to disk

[Russell Coker]

Here's an interesting article I just read.  It's just a device with a bunch of 
ATA drives inside, up to 2T of storage.  Probably anyone here could produce 
something based on ReiserFS to compete with it...


Storage start-up Avamar Technologies is launching an appliance 
this week that it claims backs up network data more quickly and 
less expensively than tape. 
http://www.nwfusion.com/news/2002/1014avamar.html?net

-- 
http://www.coker.com.au/bonnie++/     Bonnie++ hard drive benchmark
http://www.coker.com.au/postal/       Postal SMTP/POP benchmark
http://www.coker.com.au/projects.html Projects I am working on
http://www.coker.com.au/~russell/     My home page