Re: Backups

[Joe Julian <joe@xxxxxxxxxxxxxxxx>]

The rsync protocol only passes blocks that have actually changed. Raw changes fewer bits. You're right, though, that it still has to check the entire file for those changes.

On 03/23/17 12:47, Gandalf Corvotempesta wrote:

Raw or qcow doesn't change anything about the backup.

Georep always have to sync the whole file

Additionally, raw images has much less features than qcow

Il 23 mar 2017 8:40 PM, "Joe Julian" <joe@xxxxxxxxxxxxxxxx> ha scritto:

I always use raw images. And yes, sharding would also be good.

On 03/23/17 12:36, Gandalf Corvotempesta wrote:

Georep expose to another problem:

When using gluster as storage for VM, the VM file is saved as qcow. Changes are inside the qcow, thus rsync has to sync the whole file every time

A little workaround would be sharding, as rsync has to sync only the changed shards, but I don't think this is a good solution

Il 23 mar 2017 8:33 PM, "Joe Julian" <joe@xxxxxxxxxxxxxxxx> ha scritto:

In many cases, a full backup set is just not feasible. Georep to the same or different DC may be an option if the bandwidth can keep up with the change set. If not, maybe breaking the data up into smaller more manageable volumes where you only keep a smaller set of critical data and just back that up. Perhaps an object store (swift?) might handle fault tolerance distribution better for some workloads.

There's no one right answer.

On 03/23/17 12:23, Gandalf Corvotempesta wrote:

Backing up from inside each VM doesn't solve the problem

If you have to backup 500VMs you just need more than 1 day and what if you have to restore the whole gluster storage?

How many days do you need to restore 1PB?

Probably the only solution should be a georep in the same datacenter/rack with a similiar cluster, 

ready to became the master storage.

In this case you don't need to restore anything as data are already there, 

only a little bit back in time but this double the TCO

Il 23 mar 2017 6:39 PM, "Serkan Çoban" <cobanserkan@xxxxxxxxx> ha scritto:

Assuming a backup window of 12 hours, you need to send data at 25GB/s
to backup solution.
Using 10G Ethernet on hosts you need at least 25 host to handle 25GB/s.
You can create an EC gluster cluster that can handle this rates, or
you just backup valuable data from inside VMs using open source backup
tools like borg,attic,restic , etc...

On Thu, Mar 23, 2017 at 7:48 PM, Gandalf Corvotempesta
<gandalf.corvotempesta@gmail.com> wrote:
> Let's assume a 1PB storage full of VMs images with each brick over ZFS,
> replica 3, sharding enabled
>
> How do you backup/restore that amount of data?
>
> Backing up daily is impossible, you'll never finish the backup that the
> following one is starting (in other words, you need more than 24 hours)
>
> Restoring is even worse. You need more than 24 hours with the whole cluster
> down
>
> You can't rely on ZFS snapshot due to sharding (the snapshot took from one
> node is useless without all other node related at the same shard) and you
> still have the same restore speed
>
> How do you backup this?
>
> Even georep isn't enough, if you have to restore the whole storage in case
> of disaster
>
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