Raid on USB2 ?

Raid on USB2 ?

[Ken Walker]

Anybody tried a Raid1 or Raid5 on USB2.

If so did it crawl or was it usable ?

Many thanks

Ken :o)

Re: Raid on USB2 ?

[Francois Barre]

2006/2/17, Ken Walker <ken.walker@manchester.ac.uk>:
> Anybody tried a Raid1 or Raid5 on USB2.
>
> If so did it crawl or was it usable ?
>
> Many thanks
>
> Ken :o)
> -
> To unsubscribe from this list: send the line "unsubscribe linux-raid" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>

Well... Let's say... Good luck.
I am experimenting raid1 and raid5 over firewire, which is by far much
more stable (in terms of bandwidth) than usb2. According to the tests
I made, benchmarking usb2 and firewire makes usb2 dangerous to use :
connection hangs, bus collision is somewhat hasardous, bandwidth is
not really granted.
Technically, it is really possible : you will have your usb2 drives
accessible as scsi drives, put your raid on them, test them. But
sincerely, good luck.

Regards,

Re: Raid on USB2 ?

[Ewan Grantham]

I have a six disk RAID-5 array that I run using embedded Linux
(coLinux) to serve the array up using Samba to my Windows XP OS.

I've been doing this for a number of months (the dark tale is explained at:
http://a1.blogspot.com/2005/08/step-by-step-to-windows-raid-using.html),
and have had no data corruption - even when the machine has crashed
due to Windows or Power issues.

Array runs fast enough to serve video files and watch them - though
more commonly I am just copying files around. Write times are nothing
to brag about, but they aren't horrible.

Hope this helps,
Ewan

On 2/17/06, Ken Walker <ken.walker@manchester.ac.uk> wrote:
> Anybody tried a Raid1 or Raid5 on USB2.
>
> If so did it crawl or was it usable ?
>
> Many thanks
>
> Ken :o)
> -
> To unsubscribe from this list: send the line "unsubscribe linux-raid" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>

Re: Raid on USB2 ?

[Daniel Pittman]

Ken Walker <ken.walker@manchester.ac.uk> writes:

> Anybody tried a Raid1 or Raid5 on USB2.
>
> If so did it crawl or was it usable ?

Yes, I used this for two by two drive RAID-1 arrays.

It was usable, but not pleasantly.  The machine became very I/O bound,
with human scale delays introduced into previously "instant" processes
such as opening an IMAP mailbox, scanning a directory listing, etc.

I wouldn't advise more than two or three drives per USB controller, and
would expect poor performance even then.

    Daniel

Re: Raid on USB2 ?

[PFC]

>> Anybody tried a Raid1 or Raid5 on USB2.
>> If so did it crawl or was it usable ?

	Why not external SATA ?
	After all, the little cute SATA cables are a lot more suited to this than  
the old, ugly flat PATA cables...

Re: Raid on USB2 ?

[Gordon Henderson]

On Sat, 18 Feb 2006, PFC wrote:

> >> Anybody tried a Raid1 or Raid5 on USB2.
> >> If so did it crawl or was it usable ?
>
> 	Why not external SATA ?
> 	After all, the little cute SATA cables are a lot more suited to this than
> the old, ugly flat PATA cables...

Until you break a motherboard or drive SATA socket )-:

SATA might be good, but the fscking sockets are rubbish. At least you knew
where you were with good old 40-pin flat cables!

</rant>

Gordon

re: Raid on USB2 ?

[Alex Davis]

>Anybody tried a Raid1 or Raid5 on USB2.
>
>If so did it crawl or was it usable ?
>
>Many thanks
>
>Ken :o)

I have a USB raid5 consisting of 4 200GB drives. hdparm -t on the md device
gives 42 MB/s, which is nearly twice as fast as the internal drive (this is
a laptop). Since the RAID is storing large files (smallest file is about 1.5
MB), I used a stripe size of 128 K, and specified '-T largefile' to mke2fs.
All the disks, USB-to-IDE converters, and the hub are in one ATX case. It's
used to store pics from hi-res digital cameras, and video from camcorders.

I've been using the RAID for 6 months with no problems.

I code, therefore I am

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