GlusterFS / ZFS?

iamwhoiamtoday

Limp Gawd
Joined
Oct 29, 2013
Messages
493
Good morning All,
I have two storage servers, and would love to mirror them live, instead of rsync.
Currently I have Server A and Server B.

Server A:
Dual Intel six-core Xeons
48GB ECC memory
10gbps fiber to the switch
Ubuntu Server 14.04
60GB SSD OS
ZoL + 20*2TB HDs RAIDz3

Server B:
Intel dual core Celeron
32GB ECC memory
2*gigabit intel NICs on PCI-E cards
Unraid *insert current version here*
60GB SSD unused
8*3TB HDs

My plan is to install Ubuntu Server w/ZoL on each. Server A being configured in a gigantic effective raid 10, and Server B being configured as RAIDz2.

That should give me roughly 18TB on Server A, and roughly 16TB on Server B. (capacity taken using the Serve The Home raid calc, rounded down)

I don't need more than around 13TB of space right now, and I'm not intending on expanding anytime soon.

I currently use Server A as Storage for a XenServer Hypervisor over NFS.

I know what there are a lot of backup methods for me to use from Server A to Server B, especially while both running Ubuntu Server and ZFS.
Reading through the GlusterFS website, it looks to be pretty solid for live mirroring the two servers. Given the substantial difference in performance between the two systems, is GlusterFS a good choice? Is there another method for mirroring both servers live?
If needed, I don't mind setting up rsync to run every hour or so, but I'd much rather go with live replication if possible.

I am not intending on using the installed SSDs for anything beyond OS drives. Would there be a substantial performance difference if I used additional SSDs for either ZFS or GlusterFS?

Also! Please don't hold back regarding reality checks. The above is a combination of sleep deprivation and shower thoughts.
 

danswartz

2[H]4U
Joined
Feb 25, 2011
Messages
3,702
Not a gluster expert here, but the writes are going to be limited by the slowest mirror element (the raidz2). Even worse, your random write IOPS is going to be that of one spindle. Any approach that involves real-time mirroring will have that issue, AFAIK (including drbd).
 

iamwhoiamtoday

Limp Gawd
Joined
Oct 29, 2013
Messages
493
Alright, thanks for the information.

So in order to get around that performance issue, I'd be better off with a backup software that runs incrementally every X amount of time, while running the hypervisor off of Server A?

Would you recommend rsync, or is there anything special that ZFS has that you'd recommend?
 

danswartz

2[H]4U
Joined
Feb 25, 2011
Messages
3,702
It depends on what you are trying to do. If you need real-time HA (e.g. can switch to the backup without impacting the applications), you need drbd or gluster/nfs or some such. If it's just for backup, zfs snapshot send/recv is the way to go, I think. There are any number of solutions out there. One I have used is zrep (google for it). A ksh script that will do incremental zfs send streams however often you want to...
 

TGK

Weaksauce
Joined
Dec 5, 2005
Messages
71
Be sure to incorporate snapshots into your plan to avoid data issues in your primary cascading to your backup.
 
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