On 5/4/20 12:52 PM, John Sellens wrote:
On Mon, 2020/05/04 12:03:19PM -0400, Alvin Starr <alvin@netvel.net> wrote: | The client really only wants to use Centos/RHEL and ZFS is not part of that | mix at the moment.
Well, one could argue that zfs on centos is fairly well supported ... If it were purely my choice I would agree but the general rule is software that can be gotten from Centos/RH and EPEL where necessary.
| The data is actually sitting on a replicated Gluster cluster so trying to | replace that with an HA NAS would start to get expensive if it were a | commercial product.
Of course "expensive" depends on the client. An HA truenas that size, all flash is (I believe likely well) under $15K USD.
If things moved to a commercial NAS it would likely be something like Equalogic or Netapp and in that world if you have to ask the price you cannot afford it.
Ah - you didn't mention Gluster.
In theory, Gluster has geographic replication.
It does have replication but replication is not backup. a little oops like "rm -rf * somefile" will make for a very bad day if you don't catch it before it gets replicated.
And if your bricks are on LVM storage, you can use gluster snapshots as well: https://docs.gluster.org/en/latest/Administrator%20Guide/Managing%20Snapshot... to guard against accidental removals, etc.
Gluster snapshots require thinly provisioned LVM. Which is doable but will require rebuilding the systems with a different LVM config.
(I've not used either, and my glusters are quite old versions at the present time.)
Depending on how it's all configured, you may get better performance backing up the bricks, rather than backing up gluster itself. I have a two-node gluster, mirrored, so I can backup the bricks on one of the servers and get everything. Obviously that's a very simple "cluster".
Traditionally, gluster filesystem performance with large numbers of small files in a directory is horrible/pathetic. If you're backing up the gluster filesystem, you would almost certainly get better performance if your file structure is deeper and narrower, if that's possible.
We are actually backing up the bricks but the they are BIG bricks. Yes gluster has a high per file open cost but in this application that is not an issue during operation. A backup using a gluster mount would move from the world of days to weeks because of the synchronization overhead. Even with snapshots the length of time for a backup can be outrageously long.
Cheers
John
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