Xen Orchestra and Continuous Replication
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@olivier said in Xen Orchestra and Continuous Replication:
@Dashrender Speed of backup is not related to XO. Believe me, if we could done something about that, we would do it. But there is improvements on XS7 and a new patch coming will also double or triple perfs (at least).
Yeah - I know that it's not XO's fault. Considering how slow backups are on XS, I'm a bit amazed it's used. I say this slightly tongue in cheek.
I know there was talk of improvement - was the a placebo before in earlier versions of XS 7?
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@Dashrender It's not slow for everyone: I'm maxing a GBit link without any problem and we have some users having larger connections used for backup. Otherwise, we won't have clients.
Also, everyone knows (in XS world at least) that having large VMs -in terms of disk space- is not a good idea*, so it's not a common practice (and that's good).
- : for a lot of reasons, time to backup, snapshot space, Xen storage motion time, restore time and a LOT of things.
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To take your example, your 700GB backup should take 4 or 5 hours max, and then delta would be almost done instantly.
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@olivier So a question for you is with CR, would you also take forever delta's?
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@DustinB3403 This is kind of similar than delta backup, but the merge is done inside XenServer directly. After the first replication (full), it will only send the delta's.
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@olivier said in Xen Orchestra and Continuous Replication:
@Dashrender It's not slow for everyone: I'm maxing a GBit link without any problem and we have some users having larger connections used for backup. Otherwise, we won't have clients.
Also, everyone knows (in XS world at least) that having large VMs -in terms of disk space- is not a good idea*, so it's not a common practice (and that's good).
- : for a lot of reasons, time to backup, snapshot space, Xen storage motion time, restore time and a LOT of things.
How large is too large?
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@FATeknollogee said in Xen Orchestra and Continuous Replication:
@olivier said in Xen Orchestra and Continuous Replication:
@Dashrender It's not slow for everyone: I'm maxing a GBit link without any problem and we have some users having larger connections used for backup. Otherwise, we won't have clients.
Also, everyone knows (in XS world at least) that having large VMs -in terms of disk space- is not a good idea*, so it's not a common practice (and that's good).
- : for a lot of reasons, time to backup, snapshot space, Xen storage motion time, restore time and a LOT of things.
How large is too large?
Hundred's of TB's is the impression I was under.
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Hundreds of GBs starts to be harder/less flexible to play with in general. Anyway, the limit is 2TB due to VHD format.
I would prefer to use a filer and NFS/SMB to it from VMs. This way you separate your VM issues to your data/file issues.
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@olivier You prefer not to use local storage?
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@olivier yeah that sounds as if you prefer iSCSI data storage on the VM.
This way your VM is a meager 350GB c drive, and the data just hooks in from the back end.
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@FATeknollogee SR type doesn't matter in this case. I said to NOT attach large disks to VMs but to prefer, inside the VM, to mount a remote data store from a NAS/SAN/whatever.
This way your VM keeps a system disks (let's say 20 or 50GB) and that's all to backup/restore.
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@olivier said in Xen Orchestra and Continuous Replication:
@FATeknollogee SR type doesn't matter in this case. I said to NOT attach large disks to VMs but to prefer, inside the VM, to mount a remote data store from a NAS/SAN/whatever.
This way your VM keeps a system disks (let's say 20 or 50GB) and that's all to backup/restore.
That is how I read it, but it seems backwards to do so generally. Since local will always have a performance boost.
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@DustinB3403 You have to put this into context. A fast local SSD disk for a database or webserver is not a bad idea. But that won't need hundreds of GBs.
For a "datastore", there isn't any perf problem to serve larger files on a remote location (when latency isn't an issue)
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@olivier said in Xen Orchestra and Continuous Replication:
@DustinB3403 You have to put this into context. A fast local SSD disk for a database or webserver is not a bad idea. But that won't need hundreds of GBs.
For a "datastore", there isn't any perf problem to serve larger files on a remote location (when latency isn't an issue)
combating latency is the issue though.
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@DustinB3403 I mean latency of a NAS/SAN for serving files in a "normal" network isn't an issue in general (except for bad designed networks or undersized). For a DB or webserver, latency matters far more (with some order of magnitude)
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I thought all the new cool kids are doing local storage/HCI etc..
Now @olivier is saying he prefers a remote mounted datastore!
@olivier I thought you were one of the cool kids? -
So @olivier just reading this here.
It says
1.Create a CR Job
2. Manually run the first job
3. When completed export the backup Why do we need to export the backup?
4. Import it to the destination
5. Remove the local copy.I'm planning on performing identical host to host replication. Is that wrong?
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@FATeknollogee I'm not especially vulnerable to trends. I prefer solutions that works and in the same time which are not over complicated.
In this case, VMs with larger disks are always more complicated to handle in the end. That's my experience, in the XenServer world.
I don't say to never do this or that, that's just in general, you are less exposed by splitting problems into smaller pieces.
edit: that's also due to the storage architecture in XenServer. Maybe if it was far better/faster, my advice would be probably different. Having a lot of hope for SMAPIv3
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@DustinB3403 said in Xen Orchestra and Continuous Replication:
So @olivier just reading this here.
It says
1.Create a CR Job
2. Manually run the first job
3. When completed export the backup Why do we need to export the backup?
4. Import it to the destination
5. Remove the local copy.I'm planning on performing identical host to host replication. Is that wrong?
This is the doc about seeding. Do you need to make an initial seed, really?
edit: read the doc carefully, seeding is only a specific case if you need it. I think you read too fast.
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Considering that my new file server resides on a single host, yeah I'm gonna need to pre-seed the target.
