Updated XOA with kernel >5.3 to support nconnect nfs option
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On the read side :
- the legacy mode : xapi build an expor from the vhd chain
- NBD : we read individual block on the storage repository
On the write Side :
- the default file mode : we write 1 big file per disk
- block mode : we write a compressed block per 2MB data
We don't have a lot of room on the legacy mode. The NBD + block gives us more freedom, and , instinctively , should gain more from nconnect, since we will read and write multiple small blocks in parallel
What mode are you using ?
@Forza said in Updated XOA with kernel >5.3 to support nconnect nfs option:
I did a 3 x backup of a single VM hosted on an SSD drive on the same host as XOA is running, which is also pool master.
This is with
nconnect=1
:
This is with
nconnect=16
:
The transfer speed according to XOA is slightly less, but looking at the bandwidth graph, it looks like the LACP bonded network on the storage server is reaching a higher max throughput.
I will test some more with incremental backups and see if there's a difference with them.
If we ignore the
nconnect
for a second, and just look at the graphs, it seems we have a lot of possibilities to improve the backup performance if we could make the transfer more even. What is causing this type of pattern? I do not believe any coalesce was happening during this test. -
@florent hi, for the full backup test above, I used normal mode with zstd enabled. There were no snapshots of the source VM and it was stored on local ssd storage on the pool master.
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Just replying to thank you for pointing this out. I have been having very poor backup speeds for over a month and this sorted it out.
I have only used nconnect=4 and 6 for my NFS shares. -
Hi @acomav
Can you give more details on your setup and the result before/after? We might use this to update our XO guide with the new values
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@olivierlambert Hi Olivier. I'll see what I can do. I've spent the weekend cleaning up my backups and catching up on mirror transfers. Once completed, I'll do a few custom backups at various nconnect values.
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@Forza said in Updated XOA with kernel >5.3 to support nconnect nfs option:
@florent hi, for the full backup test above, I used normal mode with zstd enabled. There were no snapshots of the source VM and it was stored on local ssd storage on the pool master.
can you test a backup on an empty remote with block mode ?
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@florent Did a test on my 8.3 homelab.
Using XO on a Debian 12 VM.2 full (delta) backups using "nconnect=6" of all my 10 VM's
With block defined at remote:
without block (my normal mode):
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I'm not sure to get it with your graph. Can you write down the average values for each scenario?
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with block: 100-150 MB/s approx
without: 200-300 MB/sValues from observed NAS traffic.
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@manilx Do you mean
block
as NBD mode? -
@Forza Did another test:
A: Remote as nfs share with "Store backup as multiple data blocks"
B: same but without multiple data blocks1st backup to A,"Backup"
2nd backup to B, "Backup"
3rd backup to A, "Backup"
4th backup to B, "Delta Backup"
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@manilx This was just one VM. Did not use NBD (forgot to turn on)
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I'm a bit confused, you are comparing block based vs VHD, but did you also change the
nconnect
option between run or kept it to a specific number? (in case, which one) -
@olivierlambert allbackups done with nfs option "nconnect=6"
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@manilx 2 more and yes seems to be confusing and just to round it up.
Same VM as above
Delta (full) backup using NBD without and with "nconnect=6" in the remote setting:
with nconnect=6
nconnect=6 doesn't seem to do a lot.