[Beowulf] Re: [Gluster-devel] Size of GlusterFS installations? Hints? Alternatives?

[Amar S. Tumballi]

Hi Steffen,
 Replies inline.

On Mon, May 26, 2008 at 8:01 AM, Steffen Grunewald <
steffen.grunewald at aei.mpg.de> wrote:

> I'm looking into GlusterFS to store data on a cluster (amd64, Debian Etch)
> in a distributed way with redundancy (kind of RAID-1, two nodes mirroring
> each other). Each node has a dedicated harddisk which can be used for data
> storage, and I'm still free to decide which FS to choose.

Sure, we advice you to feel comfortable before choosing anything.


>
> For easier recovery I'd prefer not to split files across nodes (typical
> size ~ a few MB).
>
Yes, we recommend that for filesizes below few hundred MBs.


>
> Would GlusterFS be suited for such a task?

Yes.


>
> Would it scale to a couple of hundreds of disk "pairs"?

Yes.


>
> Which underlying filesystem should I choose?

you have lot of options. ext3, reiserfs, xfs, ZFS (if you use Solaris, on
BSD extended attribute support for ZFS is not yet there, hence you may not
get RAID-1 functionality of GlusterFS)

>
>
> Since I'm using my own "homegrown" kernel, which modules would I have to
> build - is it mandatory to use the patched version of fuse?

No, its not mandatory to use GlusterFS patched fuse. Its just recommended
because, it has higher I/O performance. But yes, if you want to use
GlusterFS, you need FUSE module.

If you have Infiniband setup, few IB modules (mainly ib_uverbs) are required
to get ''ib-verbs'' tranport to work. GlusterFS has native support for
Infiniband userspace verbs (ie, RDMA support) protocol, using which you can
gain a lot in performance, for both i/o intensive and low latency
applications.



> Any suggestions for the stack of translators (and their order therein)?
> How to best organize redundancy? (since I don't have it in hardware, and
> I can get hold of "missing" files *if* I know their names, this should
> be not too hard?)
>

Unify (afr1 (disk1a, disk2a.. diskNa), afr2 (disk 1b, disk2b...diskNb)...
afrN(...)) [1]

Hope the above description is understood as a tree graph.

Yes, your file resides on the hardware (ie, on backend filesystem) as is.
So, you will get the file back, even if you take the disk out.


> Any alternatives? (as fas as I know, e.g. Lustre doesn't have redundancy
> features...)
>

No idea.

Regards,
Amar

[1] disks can be mapped to remote servers too.

-- 
Amar Tumballi
Gluster/GlusterFS Hacker
[bulde on #gluster/irc.gnu.org]
http://www.zresearch.com - Commoditizing Super Storage!
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