@tsukraw multiple NBD connection will open multiple reading connection, but the writing one is always one stream per disk in incremental replication with full replication, it's one stream for read and one for write

@pierrebrunet Thanks.

@pierrebrunet I have updated my XOA and Proxies... It seems i did not see the warning on the next round of backups. Will continue to monitor now patches are installed.

I'm waiting for veeam 13.1 release as well. Will move a few things over and test out the native backup in the meantime.

@pierrebrunet I inadvertently found more information yesterday. I installed an old e492b commit on a new machine, configured identically to the original, and got a different error but the same effect. The new error is: xcp xo backup Error: read ETIMEDOUT That lead me to this page: https://xcp-ng.org/forum/topic/10799/backup-timeout-error I moved the XO machine onto the same subnet as XCP, leaving the storage behind in a different network. This fixed the issue, at least on commit e492b ... I have not yet tried it on the new release... however I am pretty confident it will be successful. If I'm honest, I think this is a tuning issue between XO and XCP. XO is now mounting an NFS share across this subnet boundary and that mount is not having any sort of performance issue, but for some reason XO times out transferring the same data from dom0? That seems off to me. It's not a probem moving XO to the other subnet, so I've done that, but maybe this deserves a look in the future.

@Rod-G These have 9.4.2-xxxx and I need to go through and update everything now that I see how far behind I am. the second VM completed fine after its reboot, something was just stuck in a dirty state and got in the way of the import or health check.

@tonyp90 great, thanks !

the last rewrite of the stream processing ( spring 2025 ) focused on stability and memory footprint, and , on a standard cpu, it tops at around 300MB/s per backup job. Your benchmarks are very interesting, and they confirm most of it. this limit was not really an issue since, in most case the xapi was limiting around 100MB/s per disk , but it will be more a more visible limit Note that master have some fixes on the memory usage (not related to backups) That's why we have started an internal workforce focused on performance, with all the teams from the kernel to the backups, including storage, network and xapi. If I can brag a little : [image: 1779106650898-afd7b59b-a4f0-4a92-88ee-2c7ba52d18bf-image.jpeg] i9 , nvme disk , backup to a nvme disk in passthrough, xoa and vm are on the same host, so it's quite far from real world data, but it shows where the limit is

@JL457 Hi, For now it looks like Wasabi is not sending us the correct date format, which is strange because we support this provider and don't usually have issues. In order to allow us to investigate further, could you send us the full backup job logs ? You can find them by clicking on the failed backup status and then on the download logs button: [image: 1779106635704-export-logs.png] Relevant XO logs would also help. If you are a client, also don't hesitate to open a ticket with an open support tunnel. Thanks.

@pierrebrunet @poddingue the size is really 2.17Tb, but showing last incremental size on the key I'll wait for the patch, this is really a visual bug, backup is working okay.

I solved the problem by installing and setting up a new Ubuntu Server. I exported the XO configuration from the old server and imported it onto the new one. What can I say—the backup started working again right away.

@McHenry I think depends if the copy is a fast clone, depending of full chain length with 13 points behind, or a full copy of its own that will be independant

@poddingue I see backups in the tasks view fine, just not mirror ones. I'm talking about v5, haven't converted to v6 yet because of missing features.

Thanks, Florent, for the explanation.

So the scheduled backup at 1pm this afternoon ran with no issue. As stated previously the Coalesces are adding now now show 2 for vm. edit - Apr 21 11:22:55 xo-ce xo-server[15617]: }, Apr 21 11:22:55 xo-ce xo-server[15617]: summary: { duration: '6m', cpuUsage: '4%', memoryUsage: '29.01 MiB' } Apr 21 11:22:55 xo-ce xo-server[15617]: } Apr 21 13:00:00 xo-ce xo-server[16924]: 2026-04-21T17:00:00.320Z xo:backups:worker INFO starting backup Apr 21 13:00:00 xo-ce sudo[16938]: xo-service : PWD=/opt/xen-orchestra/packages/xo-server ; USER=root ; COMMAND=/usr/bin/mount -o -t nf> Apr 21 13:00:00 xo-ce sudo[16938]: pam_unix(sudo:session): session opened for user root(uid=0) by (uid=996) Apr 21 13:00:00 xo-ce sudo[16938]: pam_unix(sudo:session): session closed for user root Apr 21 13:00:06 xo-ce xo-server[16924]: 2026-04-21T17:00:06.941Z xo:backups:MixinBackupWriter INFO deleting unused VHD { Apr 21 13:00:06 xo-ce xo-server[16924]: path: '/xo-vm-backups/138538a8-ef52-4d0a-4433-5ebb31d7e152/vdis/9f7daac4-80a1-41f9-8af0-99b6fe> Apr 21 13:00:06 xo-ce xo-server[16924]: } Apr 21 13:00:19 xo-ce xo-server[16924]: 2026-04-21T17:00:19.536Z xo:backups:MixinBackupWriter INFO deleting unused VHD { Apr 21 13:00:19 xo-ce xo-server[16924]: path: '/xo-vm-backups/6d733582-0728-b67c-084b-56abe6047bfc/vdis/9f7daac4-80a1-41f9-8af0-99b6fe> Apr 21 13:00:19 xo-ce xo-server[16924]: } Apr 21 13:01:23 xo-ce xo-server[16924]: 2026-04-21T17:01:23.971Z xo:backups:worker INFO backup has ended Apr 21 13:01:23 xo-ce sudo[16971]: xo-service : PWD=/opt/xen-orchestra/packages/xo-server ; USER=root ; COMMAND=/usr/bin/umount /run/xo-> Apr 21 13:01:23 xo-ce sudo[16971]: pam_unix(sudo:session): session opened for user root(uid=0) by (uid=996) Apr 21 13:01:23 xo-ce sudo[16971]: pam_unix(sudo:session): session closed for user root Apr 21 13:01:24 xo-ce xo-server[16924]: 2026-04-21T17:01:24.029Z xo:backups:worker INFO process will exit { Apr 21 13:01:24 xo-ce xo-server[16924]: duration: 83708608, Apr 21 13:01:24 xo-ce xo-server[16924]: exitCode: 0, Apr 21 13:01:24 xo-ce xo-server[16924]: resourceUsage: { Apr 21 13:01:24 xo-ce xo-server[16924]: userCPUTime: 31147905, Apr 21 13:01:24 xo-ce xo-server[16924]: systemCPUTime: 14319055, Apr 21 13:01:24 xo-ce xo-server[16924]: maxRSS: 65888, Apr 21 13:01:24 xo-ce xo-server[16924]: sharedMemorySize: 0, Apr 21 13:01:24 xo-ce xo-server[16924]: unsharedDataSize: 0, Apr 21 13:01:24 xo-ce xo-server[16924]: unsharedStackSize: 0, Apr 21 13:01:24 xo-ce xo-server[16924]: minorPageFault: 367979, Apr 21 13:01:24 xo-ce xo-server[16924]: majorPageFault: 1, Apr 21 13:01:24 xo-ce xo-server[16924]: swappedOut: 0, Apr 21 13:01:24 xo-ce xo-server[16924]: fsRead: 5648, Apr 21 13:01:24 xo-ce xo-server[16924]: fsWrite: 16101272, Apr 21 13:01:24 xo-ce xo-server[16924]: ipcSent: 0, Apr 21 13:01:24 xo-ce xo-server[16924]: ipcReceived: 0, Apr 21 13:01:24 xo-ce xo-server[16924]: signalsCount: 0, Apr 21 13:01:24 xo-ce xo-server[16924]: voluntaryContextSwitches: 65983, Apr 21 13:01:24 xo-ce xo-server[16924]: involuntaryContextSwitches: 7745 Apr 21 13:01:24 xo-ce xo-server[16924]: }, Apr 21 13:01:24 xo-ce xo-server[16924]: summary: { duration: '1m', cpuUsage: '54%', memoryUsage: '64.34 MiB' } Apr 21 13:01:24 xo-ce xo-server[16924]: } lines 617-656/656 (END)

Hello @MathieuRA , @florent Moving the discussion to this thread as it seems to be tackling the same issue: https://xcp-ng.org/forum/topic/11892/xoa-memory-usage/28?_=1776334896974 I reported my findings so far over there Best regards

@Pilow Thanks for the heads-up, you should be able to add back concurrency as it was before and get similar performance to before the refactoring.

Thank you for your feedback @kratos !

@archw Could the results you are observing be due to the fact that some of the files weren't modified in the specific delta backup that you selected as your restore point? For example: In another subdirectory there are supposed to be 7 files but in the selection window there are only two. When were these 5 "missing" files last modified?

@tsukraw No worries! Just glad that we can all help each other out!