[dundee] ESATA Linux Support
Simon Wells
swells at computing.dundee.ac.uk
Sun Mar 15 17:51:07 UTC 2009
Hi Lee,
I already have online replication of data both locally and remotely. I
already have a NAS running locally but wanted to have a decent offline
backup solution. With the questions about eSATA, I was looking for a
way to consolidate all of the various usb drives that I currently use
for offline storage into a single unit (so I can avoid the tangle of
wires), using off the shelf hdd, and do it reasonably cheaply using
fairly standard Linux tools. It looks as though eSATA fits the bill
for me at this point.
It is debatable though as to whether RAID and other forms of online
storage constitutes a *backup* system. It goes some way towards
enabling you to recover from short term hardware failure but doesn't
help when it comes to data corruption where you need to restore from a
known good backup.
Simon
Dr. Simon Wells
=============
E-mail: swells at computing.dundee.ac.uk
IM: sw3lls at yahoo.co.uk
Mail: School of Computing,
Queen Mother Building,
University of Dundee,
Dundee, DD1 4HN.
WWW: http://quiddity.computing.dundee.ac.uk/swells/blog/
Phone: +44 (0)1382 386 526
Fax: +44 (0)1382 385 509 (FAO: Simon Wells)
On 11 Mar 2009, at 00:00, Lee Hughes wrote:
> I've not used any esata, I *presume* it's looks like a normal sata
> device, and should use normal sata drivers. I doubt esata uses a
> different protocol or device driver than normal sata,.
> Why would it, the the cable run's 'outside' of your machine. ..
> (and probably has about 17 different connectors(!) I think..... i
> may be wrong!! I'm sure
> any multiplexing that's going on, is done in hardware (i.e 1 cable,
> 4 disks)
>
> If things are doom and gloomy on the esata , don't rule out using
> aoe over gigabit ethernet, give you flexible storage over the
> network, and combine that with some clever drdb -ing you can add as
> much fault tollerance as you want.
>
> http://mike.neir.org/weblog/619 is interesting.
>
> You don't exactly say what your going to use the storage for,
> gigabit ethernet cards and switches are cheap, and you can bond (if
> your using linux) gigabit together, some people I've heard have got
> over 300mb/s of read/write performance using this method, and
> striping aoe over different disk and systems. using drdb would add
> a layer of fault tollerance to the gig.
> If you go this route use PCIE gigabit adapters, not those made in
> pci format, they are cheaper, but you'll only ever get around half
> the speed that gigabit ethernet can go, as they just eat all the pci
> bus bandwidth....
>
>
>
>
>
>
> iscsi is interesting, but I just get more success with aoe at the
> moment in terms of raw performance......
>
> when you get it out of your head that storage is no longer attached
> to system, but just
> out there on the network somewhere, you can start doing some very
> clever things.
>
> you don't need to bring a server down to add sata storage, just
> configure it somewhere
> else and import it. Hotswap sata driver bays are nice, but expensive.
>
> Replicate your storage array somewhere else, may to anothe building,
> now your data
> is safe from falling asteriods.
>
> Using loopback devices, 'partitions' can be simple linux files (all
> beit large), thus you can
> do clever thing with cow's .. mooooo.
>
>
> here some links....check em..
>
> http://www.drbd.org/
>
> http://www.linuxjournal.com/article/8149
>
> http://en.wikipedia.org/wiki/ATA_over_Ethernet
>
> http://www.mjmwired.net/kernel/Documentation/networking/bonding.txt
>
>
> A guide I wrote on using aoe vblade's with cow's.
>
> http://www.etherboot.org/wiki/appnotes/cow
>
> on the other hand, if you want to get a lot of storage, and want
> support etc don't forget these people....
>
> http://www.coraid.com/
>
> http://www.coraid.com/PRODUCTS/SR2421
>
> 24 Terrabytes anyone, almost enough space to store azmodie 'film'
> collection ;-).
>
> Cheers,
> Lee
>
> --- On Mon, 9/3/09, Simon Wells <swells at computing.dundee.ac.uk> wrote:
> From: Simon Wells <swells at computing.dundee.ac.uk>
> Subject: [dundee] ESATA Linux Support
> To: "Tayside Linux User Group" <dundee at lists.lug.org.uk>
> Cc: "Simon Wells" <swells at computing.dundee.ac.uk>
> Date: Monday, 9 March, 2009, 6:56 PM
>
> Does anybody have any experience of using eSATA with Linux?
>
> I have been looking
> at something like the following:
> http://www.amazon.co.uk/EdgeStore-DAS801T-Bay-eSATA-Enclosure/dp/B001H54JWW/ref=cm_cr_pr_sims_t
>
> My plan would be to organise it as two separate JBOD arrays, using
> LVM, and
> connected via eSATA. The two arrays will give me some measure of
> redundancy and
> will make backing up my data much simpler. There is also a second
> remote server
> that holds backups and very important data is also archived to DVD.
>
> At the moment I am using a whole pile of separate external USB
> drives and want
> to simplify the system by getting all of the drives into a single
> unit. Am I
> missing anything? I have not used eSATA with Linux myself and would
> like to know
> if there are any gotchas or things that I should be aware of.
>
> Thanks,
> Simon
>
> Dr. Simon Wells
> =============
>
> E-mail: swells at computing.dundee.ac.uk
> IM: sw3lls at yahoo.co.uk
> Mail: School of Computing,
> Queen Mother Building,
>
> University of Dundee,
> Dundee, DD1 4HN.
> WWW: http://quiddity.computing.dundee.ac.uk/swells/blog/
> Phone: +44 (0)1382 386 526
> Fax: +44 (0)1382 385 509 (FAO: Simon Wells)
>
>
>
>
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