Xen Orchestra web UI becomes unresponsive when an NFS backup remote goes offline

Reply to Xen Orchestra web UI becomes unresponsive when an NFS backup remote goes offline on Thu, 05 Nov 2026 15:21:14 GMT

acebmxer — Thu, 05 Nov 2026 15:21:14 GMT

Just leaving it on 24/7 winter is here now or so we thought (its 75f outside today) . If there is any update on this i would try again. but as it seems you are having the same issue i did then, it does not appear to be fixed.

Reply to Xen Orchestra web UI becomes unresponsive when an NFS backup remote goes offline on Thu, 05 Nov 2026 15:11:15 GMT

frb94 — Thu, 05 Nov 2026 15:11:15 GMT

@acebmxer So what are you doing now? Given the manual, NFS is the way, but i can't have the remote available h24 and also i would like to have a functioning XO

Reply to Xen Orchestra web UI becomes unresponsive when an NFS backup remote goes offline on Thu, 05 Nov 2026 14:53:06 GMT

acebmxer — Thu, 05 Nov 2026 14:53:06 GMT

@poddingue @frb94

Yes if I recall (I may not have stated on the forum) that I still ended up with issues and just abounded the idea. Not sure on the time line when they attempted a patch to when i stopped disabling the remote.

Reply to Xen Orchestra web UI becomes unresponsive when an NFS backup remote goes offline on Thu, 05 Nov 2026 14:39:30 GMT

frb94 — Thu, 05 Nov 2026 14:39:30 GMT

@poddingue

Thank you very much for the answer.

This is my idea for now, but i'll look into better ways to do this.

*/5 * * * * /opt/scripts/enabledisableremote.sh

#!/bin/bash

export PATH="/usr/local/bin:/usr/bin:/bin:$HOME/.npm-global/bin:$PATH"

REMOTE="9fc232df-4d0c-4a15-93b5-c0585c1dd9c9"
NAS="10.0.0.28"

# Stato attuale del Remote
CURRENT=$(/usr/local/bin/xo-cli remote.getAll --json | jq -r --arg id "$REMOTE" '.[] | select(.id == $id) | .enabled')

# Stato desiderato in base alla raggiungibilità del NAS
if ping -c 1 -W 2 "$NAS" > /dev/null 2>&1; then
    DESIRED=true
else
    DESIRED=false
fi

# Cambia stato solo se necessario
if [[ "$CURRENT" == "true" || "$CURRENT" == "false" ]]; then
    if [[ "$CURRENT" != "$DESIRED" ]]; then
        /usr/local/bin/xo-cli remote.set id="$REMOTE" enabled="$DESIRED"
    fi
fi

Reply to Xen Orchestra web UI becomes unresponsive when an NFS backup remote goes offline on Thu, 05 Nov 2026 14:33:19 GMT

poddingue — Thu, 05 Nov 2026 14:33:19 GMT

This looks like the same thing @acebmxer ran into in July (https://xcp-ng.org/forum/topic/12339), and your libuv reading matches what the XO devs wrote in https://github.com/vatesfr/xen-orchestra/pull/10587.

As I read their write-up, with a hard mount every background operation on the dead remote (listing backups, retries) holds one of xo-server's file-access threads until the NAS comes back, and once they're all taken the web UI can't be served either.

Olivier's advice back then (https://xcp-ng.org/forum/post/106632) was to disable the remote while the NAS is still up and only then power it off, and acebmxer scripted that on the Synology so the remote gets disabled at shutdown and enabled again at startup through the XO API.

If XO is already stuck, XO 6.10.0 added xo-server-db disable-remote , which you run while xo-server is stopped so the remote isn't mounted again on the next start; your November 1 build should have it if I read the dates right, but I haven't tried it myself.

About UV_THREADPOOL_SIZE I'm only guessing, but since a hung NFS call never gives its thread back I'd expect a bigger pool to just take longer to fill, and the PR says they tried capping the threads one remote can use and dropped the idea for now. @Team-XO-Backend will know better than me whether more is planned.