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[Veritas-bu] Disk backup - Storage Hardware configurations
2006-03-24 15:02:00
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Subject: |
[Veritas-bu] Disk backup - Storage Hardware configurations |
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From: |
tim.berger AT gmail DOT com (Tim Berger) |
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Date: |
Fri, 24 Mar 2006 10:02:00 -1000 |
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Agreed. 70MB/sec writes is disappointing but acceptable for my
requirements. On a fast cpu machine you'll see better performance with
software raid. That's normal. There's lots of other reasons to go with
3ware. Here's what led me there:
- Auto-sector repair. With big disks, this is critical. I've lost softwar=
e
raids in the past due to latent bad block loss that led to more than one
disk getting failed out. All big disks have this problem.
- Very reliable driver support. smartd support.
- Hot swap support, good management interface.
Software raid is good for some things, but I would not use it in a machine
that requires high uptime. Each of my media servers has 24 400GB drives so
ease of managment and reliability is critical. I used to strictly use
software raid. No more.
On 3/23/06, Sander <sander AT humilis DOT net> wrote:
>
> Tim Berger wrote (ao):
> > I have two Linux media servers setup with 3ware 9500S controllers
> > using raid "50" with seagate disks. With our configuration this is
> > two raid 5's of 6 disks each that are then striped together. I get
> up
> > to about 70MB/sec writes and 300MB/sec reads after the readahead is
> > tweaked up.
>
> I'm not impressed at all by 70MB/sec on a raid config. I currently have
> eight Maxtor 300GB disks (slow) sw raid5 on a Marvell 8-port sata
> controller, and see at least twice as much for writing.
>
> Not to mention that the Marvell 8-port controller is much, much cheaper
> than a 3ware 9500S controller.
>
> With 3 controllers and 24 WD Raptors raid5, 500MB/sec should not be a
> problem.
>
> Can you try this for me, just for fun? It creates four 10GB files.
>
> for i in `seq 4`
> do time dd if=3D/dev/zero of=3Dbigfile.$i bs=3D1024k count=3D10000
> time dd if=3Dbigfile.$i of=3D/dev/null bs=3D1024k count=3D10000
> done
> time rm bigfile.*
>
> With a modern 'dd' it will also output the MB/sec speed.
>
> Kind regards, Sander
>
> --
> Humilis IT Services and Solutions
> http://www.humilis.net
>
--
-Tim
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Agreed. 70MB/sec writes is disappointing but acceptable for my requir=
ements. On a fast cpu machine you'll see better performance with soft=
ware raid. That's normal. There's lots of other reasons to go w=
ith 3ware. Here's what led me there:
<br><br>- Auto-sector repair. With big disks, this is critical. =
I've lost software raids in the past due to latent bad block loss that led=
to more than one disk getting failed out. All big disks have this pr=
oblem.<br><br>
- Very reliable driver support. smartd support.<br><br>- Hot swap sup=
port, good management interface.<br><br>Software raid is good for some thin=
gs, but I would not use it in a machine that requires high uptime. Ea=
ch of my media servers has 24 400GB drives so ease of managment and reliabi=
lity is critical. I used to strictly use software raid. No more=
.
<br><br><div><span class=3D"gmail_quote">On 3/23/06, <b class=3D"gmail_send=
ername">Sander</b> <<a href=3D"mailto:sander AT humilis DOT
net">sander@humilis=
.net</a>> wrote:</span><blockquote class=3D"gmail_quote" style=3D"border=
-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-lef=
t: 1ex;">
Tim Berger wrote (ao):<br>> I have two Linux medi=
a servers setup with 3ware 9500S controllers<br>>  =
;using raid "50" with seagate disks. With o=
ur configuration this is<br>> two raid 5's of 6 d=
isks each that are then striped together. I get up
<br>> to about 70MB/sec writes and 300MB/sec read=
s after the readahead is<br>> tweaked up.<br><br>=
I'm not impressed at all by 70MB/sec on a raid config. I currently have<br>=
eight Maxtor 300GB disks (slow) sw raid5 on a Marvell 8-port sata
<br>controller, and see at least twice as much for writing.<br><br>Not to m=
ention that the Marvell 8-port controller is much, much cheaper<br>than a 3=
ware 9500S controller.<br><br>With 3 controllers and 24 WD Raptors raid5, 5=
00MB/sec should not be a
<br>problem.<br><br>Can you try this for me, just for fun? It creates four =
10GB files.<br><br>for i in `seq 4`<br>do time dd if=3D/dev/zero of=3Dbigfi=
le.$i bs=3D1024k count=3D10000<br>time dd if=3Dbigfile.$i of=3D/dev/null bs=
=3D1024k count=3D10000
<br>done<br>time rm bigfile.*<br><br>With a modern 'dd' it will also output=
the MB/sec speed.<br><br> K=
ind regards, Sander<br><br>--<br>Humilis IT Services and Solutions<br><a hr=
ef=3D"http://www.humilis.net";>http://www.humilis.net
</a><br></blockquote></div><br><br clear=3D"all"><br>-- <br>-Tim
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