Lustre discuss - May 2006 - general question

Martinus wrote:
> I have multiple pc''s, with HDD, that I would like to "bring
> together"
> 
> i.e.
> 
> 5 x pc''s with 20Gb HDD each -- I want to have 100Gb of space
available
> on a system.  I can then take ext3/reiserfs and create a JFS of that
> 100 Gb ? Which can then be software mirrored to another x boxes that
> == 100 Gb ?
> 
> If lustre can do this, how flexible is it ?  Can I add another pc with
> a 100Gb drive "on the fly" ? (not taking mirror conditions into
> consideration).
Lustre will allow you to create a file system with 100 GB of available
space from those 5 disks, but not exactly in the way that you describe.

You would run the Lustre object storage server software (OSS) on each of
those five nodes.  Lustre would mount and manage those disks behind the
scenes, and present one network-mountale Lustre file system.  It would
not provide a 100GB block device for you to format as ext3, reiserfs, etc.

There is one snag, though; if you only have 5 nodes, then you will
presumably also want each of those nodes to be a Lustre client, and
mount the file system.  Configurations with a client and an OSS on the
same node are not completely stable yet; there are bad memory-management
interactions between the page cache on the "client" side and the disk
file system on the "server" side.

We will fix this when we get time, but it''s quite involved, and we have
no paying customers who want to run in this configuration.
> If all this is possible, then I can imagine RAID 1+0 / 0+1 setups ?
Today Lustre will only allow you to configure your storage servers in a
raid 0 setup, with individual files striped across one or more servers.
 Lustre 2.x (or late in the 1.x series) will allow you to configure
mirroring between your servers.  Until then, if you want redundant
storage, you need to configure software raid on the backend, and tell
Lustre to use that mirrored block device.

Hope this helps--

-Phil

Hello lustre-discuss,

I have read trough your archives, and found one person asking whether
lustre is what he needs... some of my questions was answered there,
but not all :)

Now I would like to ask:

I have multiple pc''s, with HDD, that I would like to "bring
together"

i.e.

5 x pc''s with 20Gb HDD each -- I want to have 100Gb of space available
on a system.  I can then take ext3/reiserfs and create a JFS of that
100 Gb ? Which can then be software mirrored to another x boxes that
== 100 Gb ?

(this is just an example, as I am well aware of the _little_ fact that
there is 200Gb HDD available).

If lustre can do this, how flexible is it ?  Can I add another pc with
a 100Gb drive "on the fly" ? (not taking mirror conditions into
consideration).

A reply by Andreas Dilger on Tue, 21 Oct 2003 13:08:09 -0600 to
Nicholas Henke suggest to me that I can.

If all this is possible, then I can imagine RAID 1+0 / 0+1 setups ?

Or am I a rambling mad man now ? :)

-- 
Best regards,
 Martinus                          mailto:martinus@nafta.lt