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Home > Archive > Data Storage > March 2005 > Rackmount Serial ATA
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Rackmount Serial ATA
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| Does anyone make a rackmountable drive array that is cheap and
uses hotswap Serial ATA drives? I know about the Adaptec
2410SA , but does anyone make a larger external enclosure that
can hold 10+ SATA drives? I am interested in RAID enclosures
as well, but I would be happy with a JBOD enclosure, and I will
handle the RAID management from the host in software.
--
Will
Internet: westes at earthbroadcast.com
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| Torbjorn Lindgren 2005-03-06, 5:45 pm |
| Will <DELETE_westes@earthbroadcast.com> wrote:
>Does anyone make a rackmountable drive array that is cheap and
>uses hotswap Serial ATA drives? I know about the Adaptec
>2410SA , but does anyone make a larger external enclosure that
>can hold 10+ SATA drives?
The question is how do you connect them to the controller if that's in
another machine? Yes, individual SATA cables can be long enough, but
it'd be a mess and I really wonder if it's not going to sensitive to
noise too.
There are a bunch of FC attached SATA JBOD enclosures, Google for more
information (that's where I found them). But then you'd need to either
do software RAID or use a FC RAID controller instead (probably far
more expensive than those SATA RAID controllers).
Another option is to get a rack case which combines space for
motherboard and SATA disks!
SuperMicro has two 3U cases with space for motherboard and 15 SATA
disks, that's a nice little "little" file-server there...
But if you're going for SATA RAID controller and want to run RAID5 you
should consider which controller you're going to use (RAID1/0/10 puts
much less load on the controller, so it MIGHT not matter as much).
Also, with RAID5 you might want a BBU (without it you can choose
between low RAID5 write performance or unsafe operation), but most of
the controllers with many channels have this as an option.
Adaptec has long had a bad performance reputation with their SCSI
controllers, and there have been complaints of very bad performance of
their SATA RAID controllers in this group.
The safe bet is probably 3ware 9500, they've been in the SATA RAID
segment much longer than the others and been known for performance,
and the 9500 seems to be quite a bit faster than their older 7500/8500
controllers. One drawback is that they don't make controllers with
more than 12 SATA ports, and with the case above 15 (or more) would
have been better (so either use 12 RAID disks or two controllers).
I see that LSI logic, the other "classic" provider also has SATA RAID
controllers, but I've never tried on and to even guess what
performance they might have I'd first want to know if they're based on
the AMI or Mylex firmware :-) (they own both and the reputation of
those two are rather different, though both used to be miles ahead of
Adaptec).
>I am interested in RAID enclosures as well, but I would be happy with
>a JBOD enclosure, and I will handle the RAID management from the host
>in software.
I've looked a bit more at that, there are a LOT of options in that
market, most of them available with FC and SCSI interfaces. But in the
end we ended up with a SuperMicro machine with the SC933 chassi
mentioned above (and 3ware 9500S-12 + 9500S-4LP)
We were mainly looking at Nexsan (various options, 42 SATA/4U and 8 SATA/1U
is damned impressive) and Infortrend EonStor, but that was mostly due
to that being what we were being offered.
Other ones I found with a quick Google: TechnoLand, ExcelMeridian,
StorCase, Adjile Systems, Maxtronic, Enhance Technology, Promise,
Peripheral Storage...
I have a feeling there are much fewer RAID controllers than boxes,
that much of the difference is in packaging/format. I do wonder how
many "standard" controllers there are, 2-3 perhaps? (plus several used
only by the manufacturer themself).
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| Torbjorn Lindgren 2005-03-08, 5:45 pm |
| Torbjorn Lindgren <tl@none.invalid> wrote:
>Will <DELETE_westes@earthbroadcast.com> wrote:
[..][vbcol=seagreen]
>But if you're going for SATA RAID controller and want to run RAID5 you
>should consider which controller you're going to use (RAID1/0/10 puts
>much less load on the controller, so it MIGHT not matter as much).
http://www.tweakers.net/reviews/557
Those Areca controllers looks really interresting, and a few others
are also possible contenders.
Besides the tested controllers they look at several other alternatives
at page 15, including Adaptec. It isn't exactly flattering, but seems
to match what others say about them.
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| If you are going the route of PCI cards inside of a Windows or
Linux box, then what is the best way to just expose those serial
ATA disks as JBOD to the host OS, and not put RAID in the card?
If I were going the route of PCI cards I would be tempted to
manage this through Veritas Volume Manager since it has far more
capability than anything in the card's firmware.
--
Will
Internet: westes at earthbroadcast.com
"Torbjorn Lindgren" <tl@none.invalid> wrote in message
news:ytlXd.665694$Zm5.95380@news.easynews.com...
> Torbjorn Lindgren <tl@none.invalid> wrote:
and[vbcol=seagreen]
that[vbcol=seagreen]
> [..]
RAID5 you[vbcol=seagreen]
(RAID1/0/10 puts[vbcol=seagreen]
much).[vbcol=seagreen]
>
> http://www.tweakers.net/reviews/557
>
> Those Areca controllers looks really interresting, and a few
others
> are also possible contenders.
>
> Besides the tested controllers they look at several other
alternatives
> at page 15, including Adaptec. It isn't exactly flattering, but
seems
> to match what others say about them.
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| Torbjorn Lindgren 2005-03-09, 5:46 pm |
| Will <DELETE_westes@earthbroadcast.com> wrote:
>If you are going the route of PCI cards inside of a Windows or
>Linux box, then what is the best way to just expose those serial
>ATA disks as JBOD to the host OS, and not put RAID in the card?
>If I were going the route of PCI cards I would be tempted to
>manage this through Veritas Volume Manager since it has far more
>capability than anything in the card's firmware.
Well, I'd expect that most or all of these cards can run as simple
JBOD controllers too. Another option is to use multiple "plain"
controllers, but they tend to top out at 4 SATA disks each, and at
least some of them you can only have a limited amount of cards! (even
if you had enough PCI-X/E slots left)
Another question is how you're going to do with write cacheing, RAID
1/0 might be able to get decent performance without it, but even with
that you probably want some kind of BBU (battery backed memory). With
RAID-5 (and 6) the hit is far worse, and unless you're going to do
almost no writes you probably need it for RAID-5.
I suspect that BBU equipped cards should cache writes even to JBOD
disks, so that might be one option. Another possibility is to try to
get Veritas to handle it, the question I can't answer is if there are
hardware that provides this functionality and that Veritas can use
(and how much work it would to make it work).
I'd trust many of the full hardware controllers more than I'd trust
Veritas (their problem IS significantly easier than what Veritas has
to solve), but others may differ. But Veritas is certainly better than
doing RAID with the "hostbased" controllers, in this test HighPoint,
Promise and RAIDCore...
*If* you don't need a controller with BBU and want to run in JBOD mode
the card wouldn't have to have a fast CPU, but it would need
high-speed PCI-X/PCI-E internal and external busses to avoid
bottlenecks...
The HighPoint RocketRaid is by far the cheapest of the 8-port card and
seems to be the obvious candidate if one were to try this (the other
possible alternative is RAIDCore, but it's much closer to Areca/Tekram
cards in price, and for this usage it shares many of the limitation
that the RocketRaid card has)
If you need cards with BBU that reduces the selection drastically,
leaving only 3ware 9500S, Areca and LSI. The LSI is a 6-lane
controller and not a serious contender for this. The 3ware has some
limitations (including PCI bus speed) so the equally priced Areca (or
Tekram) is probably the one to check out.
You mentioned Adaptec 2410SA earlier, I suspect that they may be a bit
closer to decent performance when used this way (not limited by the
IOP), but it's not really guaranteed because rumor claims that part of
their problem is excessive copying as part of the caching, if you use
the BBU option this could still hurt you..
Also, they're still limited by their slow internal AND external PCI
interfaces. There are BBUs for them, but on the other hand they tend
cost almost as much as the Areca and 3ware 9500S, and even the
similarly limited 3ware will probably work better.
But nothing ever beats trying them out with the applications you plan
to use, but even if you managed to borrow the cards for testing it
could take quite a bit of time to test all this.
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| Mark Landin 2005-03-21, 5:46 pm |
| On Sat, 5 Mar 2005 14:11:43 -0800, "Will"
<DELETE_westes@earthbroadcast.com> wrote:
>Does anyone make a rackmountable drive array that is cheap and
>uses hotswap Serial ATA drives? I know about the Adaptec
>2410SA , but does anyone make a larger external enclosure that
>can hold 10+ SATA drives? I am interested in RAID enclosures
>as well, but I would be happy with a JBOD enclosure, and I will
>handle the RAID management from the host in software.
Ask and ye shall receive:
http://www.caeneng.com/products/mod...metsata16eu.htm
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