[PVE-User] efficient backup of VM on external storage.

[Fabrizio Cuseo]

All my answers below:

> 1. would you please share your hardware specs of Ceph storage cluster
> and PVE Box and the connectivity of all boxes.

You can use legacy linux servers for Ceph Storage; of course, you can use cheap servers (ex: HP Microserver, with 4 sata disks) if you don't mind about performances; if you want performances, you can use 3 xeon based server, not less of 8Gbyte ram (16Gbyte is better), and several SAS disks for each server. For network connections, use 2/4 giga ethernet in a single bond. 
You can also use every kind of legacy linux server, or a virtual machine on each proxmox node, using 2 or more local disks (not used for other proxmox local storage), like Vmware does with VSA (virtual storage appliance); performances can be enough or not depending on your needs.

> 2. do you relay upon only replication. dont you take the backup of
> VM? if yes then again would you please throw some light on your
> strategy in reference to my question in first message.

Replication is never enough; you always need a backup with a retemption strategy; use another storage (a cheap soho nas with 2/4 sata disk in raid 1/10)
 
> 3. Any recommended how to for ceph and PVE.

You can find an howto on proxmox ve wiki, ( http://pve.proxmox.com/wiki/Storage:_Ceph ) and of course you can read on ceph home page.

 
> 4. is your setup Ceph cluster is like DRBD active/passive with heart
> beat. if one down second will auto up. with a second or 2 downtime?

Replication on a clustered storage is something different; every "file" is splitted in several chunks (blocks) and every chunk is written on 2 or more servers (depending of replication level you need); so if one of the nodes of the ceph storage cluster dies (or if you need to reboot, change hardware, move location), the cluster can work in degraded mode (as a raid volume), but differently from raid, if you have 3 or more servers, and your replica goal is 2, the cluster begin to write the clusters with only 1 copy on the other servers; when your dead server can rejoin the cluster, it will be syncronized with every change... so always works like a charme.

 
> Sorry for involving DRBD all the time since i have only worked on
> DRBD clustering, only concept of mine in clustering starts and ends
> on DRBD+heartbeat :) and as you also know that DRBD work little
> differently and have some limitations too. so please dont mind.


Is really different, and (for me) better. A storage cluster is not only redundant, but you can expand it lineary, with other server and/or disks, having more space (theoretically infinite space), more redundancy (if you change your replica goal from 2 to 3, for example), and more performance because you have more cpu, more disk, more IOPS.

Regards, Fabrizio 
 
> 
> Thanks,
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> Regards, Fabrizio
> 
> 
> 
> ----- Messaggio originale -----
> Da: "Muhammad Yousuf Khan" < sirtcp at gmail.com >
> A: pve-user at pve.proxmox.com
> Inviato: Sabato, 5 ottobre 2013 10:58:41
> Oggetto: [PVE-User] efficient backup of VM on external storage.
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> i have never worked on external storage just worked on drbd on local
> storage/system drives.
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> Scenario is:
> for example. i have two external storage and 1 Proxmox Machine.
> i am using 1G NICs to connect all nodes
> 
> the storage are connected to each other from another link but no
> replication done b/w storage boxes mean they are no failover to each
> other. and both the storage are connected to Proxmox. i am using
> primary storage to run 3 machines on NFS or iSCSI. note that machine
> are running on primary storage over a single 1G ethernet link/single
> point of failure.
> 
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> 
> now lets say. i want VM1 backedup to secondary storage. however i
> dont want my backup traffic to effect my primary link where 3
> machines are active.
> 
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> any suggestion to achieve that.
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> Thanks.
> 
> 
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> 
> --
> ---
> Fabrizio Cuseo - mailto: f.cuseo at panservice.it
> Direzione Generale - Panservice InterNetWorking
> Servizi Professionali per Internet ed il Networking
> Panservice e' associata AIIP - RIPE Local Registry
> Phone: +39 0773 410020 - Fax: +39 0773 470219
> http://www.panservice.it mailto: info at panservice.it
> Numero verde nazionale: 800 901492
> 
> 

-- 
---
Fabrizio Cuseo - mailto:f.cuseo at panservice.it
Direzione Generale - Panservice InterNetWorking
Servizi Professionali per Internet ed il Networking
Panservice e' associata AIIP - RIPE Local Registry
Phone: +39 0773 410020 - Fax: +39 0773 470219
http://www.panservice.it  mailto:info at panservice.it
Numero verde nazionale: 800 901492