[Lustre-discuss] howto make a lvm, or virtual lvm?

[Eudes PHILIPPE]

The problem is if i have:
Server MDS1 for mdt and mgt
Server OSS1 for ost1
Server OSS2 for ost2
Server OSS3 for ost3
.
.
.

-----Message d'origine-----
De : Ben Evans [mailto:Ben.Evans at terascala.com] 
Envoyé : mercredi 15 décembre 2010 20:33
À : Eudes PHILIPPE
Objet : RE: [Lustre-discuss] howto make a lvm, or virtual lvm?

First to clear up some terminology:

You have
Server MDS1 for mdt and mgt
Server OSS1 for ost1 and ost2

Client1 which mounts the filesystem from all the MDS and OSS servers.

On Client1, you create the two files, each mapped using the "lfs setstripe" command to a specific OST.

When you run "lfs getstripe $filename" you should see a list of all the OSTs that it is mapped to.

Loop mount the files on client1.

>From LVM, use pvcreate to create virtual disks of a fixed size.
Use VG create on client1 to create your single, large volume with a stripe size of 1MB.

At this point, you should have a RAID-0 group over those two files on the back-end, that you could now create a filesystem on and export through NFS (for example), or whatever you want to do.

LVM may or may not have a RAID-5 setting (I don't recall), but other utilities in Linux have it, and you should be able to leverage them to create something extensible.

-----Original Message-----
From: lustre-discuss-bounces at lists.lustre.org [mailto:lustre-discuss-bounces at lists.lustre.org] On Behalf Of Eudes PHILIPPE
Sent: Wednesday, December 15, 2010 2:14 PM
To: lustre-discuss at lists.lustre.org
Subject: Re: [Lustre-discuss] howto make a lvm, or virtual lvm?

Mhhh... it's strange, but it's done! Except... if each ost are on different servers... the creation of lvm you mean, is on one ost server. And on the client server which mount the mds partition, there is one or several ost on several servers.
I want to merge ALL ost on a "similar" lvm, or, a  raid 5(?) over network

Are you sure it is the better way in a production environment ?

-----Message d'origine-----
De : Ben Evans [mailto:Ben.Evans at terascala.com] Envoyé : mercredi 15 décembre 2010 19:55 À : Eudes PHILIPPE; lustre-discuss at lists.lustre.org Objet : RE: [Lustre-discuss] howto make a lvm, or virtual lvm?

Phillipe,

One way to circumvent this would be to create one file on each OST, loop mount them on the client and use pvcreate on each to size them at ~950 MB.  Once you've done that create a VG (striped, stripe size should be exactly 1M (lustre's preferred I/O size), and you should be good to go.

It's been awhile since I've played around with doing this, but it's the basic idea.

-----Original Message-----
From: lustre-discuss-bounces at lists.lustre.org [mailto:lustre-discuss-bounces at lists.lustre.org] On Behalf Of Eudes PHILIPPE
Sent: Wednesday, December 15, 2010 12:06 PM
To: lustre-discuss at lists.lustre.org
Subject: [Lustre-discuss] howto make a lvm, or virtual lvm?

Hello

I’m newbie on lustre ☺

Currently, i make some test on virtual machines.

I’ve:
- Server mds1 for mdt mgs
- Server ost1 for data, with 2 drives 1Go (for test, it's some virtual machines)
- Server client to mount mds

On server mds1
/dev/sda3              93G  461M   87G   1% /mds

On server ost1
/dev/sdc             1008M  64M  967M  2% /home/ost2
/dev/sdb             1008M  957M   68K 100% /home/ost1

(
Or
On server ost1
/dev/sdb             1008M  957M   68K 100% /home/ost1

On server ost2
/dev/sdb             1008M  64M  967M  2% /home/ost2
}


On client
192.168.45.20 at tcp0:/large-fs        2,0G  1,3G  629M  68% /home

At the end, I want (if it's possible), a raid 5 over Ethernet, or, 1 physical raid 5 on each ostX and a big lvm I can extend as I want....

For my first test, I upload on client a file (1.8 Go) (each ost have 1 Go) The problem, is, when sdb is full, he stop the copy, and don't continue on ost2

Maybe I must create a lvm, but I don't found howto to (maybe it's possible to create lvm without format when I add others ost later..)

Questions:
- it's the good way?
- How I can write a 1.8Go (one file) on the 2 os, one part on ost1, one and final part on ost2

Regards


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