docker-timemachine: Share inaccessible (Connect as fails), but daemon works, etc.

Not sure if problem is not related to a move to arm64v8/alpine:latest as base image. It removed the other problem mentioned here: https://github.com/mbentley/docker-timemachine/issues/81

Every time trying to mount the share (Connect as) it fails and talks about server being inaccessible. Tcpdump shows proper connection and it is at application layer. Logs showed below for each connection:

tdb(/var/cache/samba/gencache.tdb): tdb_mutex_open_ok[/var/cache/samba/gencache.tdb]: Mutex size changed from 241664 to 401408
tdb(/var/cache/samba/gencache.tdb): tdb_mutex_open_ok[/var/cache/samba/gencache.tdb]: Mutex size changed from 241664 to 401408
tdb(/var/cache/samba/gencache.tdb): tdb_mutex_open_ok[/var/cache/samba/gencache.tdb]: Mutex size changed from 241664 to 401408

Removing gencache.tdb seems to fixed the problem, at least can connect as to the share.

After another container restart below has popped up:

Failed to fetch record!
pcap cache not loaded
error in mds_init_ctx for: /opt/user
_mdssvc_open: Couldn't create policy handle for TimeCapsule-user

It is still possible to connect as though opening mounted folders (Backups.backupdb) takes ages and produces more of

Failed to fetch record!
pcap cache not loaded

This is probably due to deletion of gencache.tdb, so it rebuilds it, hence slowness, can see very low I/O activity at the disk (400-1500kB/s) and on outgoing interface related volume of data being pumped out back to Mac (below is iostat (30)

Device:            tps   Blk_read/s   Blk_wrtn/s   Blk_read   Blk_wrtn
sda              14.00      1648.00         0.00       1648          0

This suggest more or leas that it might be a lot of hdd head movement, though iowait is not that high either. So a lot of small reads I take it.

There is already ~400GB of backup files, so not sure if it’s not going through all of that and not sure how to speed it up. Glanced at: https://github.com/mbentley/docker-timemachine/issues/75, which can be related.

Any hints on what to look at or to speed it up or potential sources and ideas how it could be sped up if at all?