leaf-coalesce: EXCEPTION. " Unexpected bump in size"
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@olivierlambert Of course. It's a new time related to this issue: https://xcp-ng.org/forum/topic/6732/vdi-could-not-be-coalesced/7?_=1692200431466
@topsecret What's your host configuration? CPU and drive please? An overused CPU can be the cause of the problem, a slow disk, too many writes in VMs... Many factors can play a role.
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@ronan-a This cluster based on Huawei CH121 V5 servers with Intel(R) Xeon(R) Gold 5120T CPU @ 2.20GHz, 320 Gb RAM and Intel(R) Xeon(R) Gold 6138T CPU @ 2.00GHz, 512 Gb RAM. We have more than a half free RAM and CPU on each server according to Xen Orchestra. SAS storage free capacity is about 45% (17Tb).
Problem disks capacity are about 2Tb
We can't stop virtual machines, it affects productive service -
I powered off one VM with two 2Tb disks, overall coalesce time was about 3-4 hours.
Running VM still has VDI to coalesce. I found proccess "/usr/bin/vhd-util coalesce --debug -n /dev/VG_XenStorage-de024eb7-ce14-5487-e229-7ca321b103a2/VHD-b5d6ab41-50dc-4116-a23c-e453b93ce161"
Can I run it again to parallel coalesce process? -
Hello!
Same error " Unexpected bump in size" on different servers with xcp-ng 8.2.0.
Hardware RAID5 and RAID10 used, with 8 SDD DC500M-DC600M. Only power off VM, Rescan, and wait about 8-10 minutes helps. Any solution or any updates can solve the problem?Thank you!
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Hi,
Your SR is probably coalescing slower than you are adding data to your disk in live, and can't catch up.
You might try to use CBT-enabled backup with XO to reduce the snapshot size.
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Thank you!
But, disk IO operations is very low during coalescing. All users are logged off from the server.
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So I can only suppose it's a Windows guest? Those guest are always writing a non-negligible quantity, and if your coalesce speed is slower than this, then, the coalesce process will detect data has grown faster than it merged, and it will fail.
There's another possibility, to modify some coalesce timing to be more aggressive, that might solve it on your end.
Following an old feedback on Github, you can try those values: https://github.com/xcp-ng/xcp/issues/298#issuecomment-557805054
closed XCP-ng 8.0 / CH 8.0 coalesce issues #298
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Thank you!
Yes, Windows VMs with guest tools installed.
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Keep us posted on the result
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Dependig on hardware, any xcp-ng 8.2.0 host must be modified, if it running Windows VMs? My xcp-ng 8.2.0 host servers has powerful disk system, based on SSD and hardware RAID controller with onboard cache.
Thank you!
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No, it really depends on many factors. There's no universal tuning.
