Unable to start more than 14 domUs - libxl__xs_transaction_commit: could not commit xenstore transaction

["J. Roeleveld" <joost@xxxxxxxxxxxx>]

Hi all,

I upgraded to Xen 4.12.2 recently and since the upgrade, I am unable to start 
more than 14 domUs.

The error, when trying to start the 15th, is:
Parsing config from /etc/xen/boot/stage7/dbtest
libxl: error: libxl_xshelp.c:265:libxl__xs_transaction_commit: could not 
commit xenstore transaction: No space left on device
libxl: error: libxl_xshelp.c:265:libxl__xs_transaction_commit: could not 
commit xenstore transaction: No space left on device
libxl: error: libxl_create.c:1318:domcreate_launch_dm: Domain 20:unable to add 
disk devices
libxl: error: libxl_domain.c:1038:libxl__destroy_domid: Domain 20:Non-existant 
domain
libxl: error: libxl_domain.c:993:domain_destroy_callback: Domain 20:Unable to 
destroy guest
libxl: error: libxl_domain.c:920:domain_destroy_cb: Domain 20:Destruction of 
domain failed



The domUs showing the issue get the disks from a driver-domain.
All this was working correctly using older Xen versions and no config changes 
have been done.

Unfortunately, I am unable to find anything further in the logs and my google-
fu is not helping either as all I find is for much older versions.

If anyone has any further ideas on how to further analyse this?

If I stop 1 domU, I am able to start another one, so I am confident it has to 
do with amount of domUs running and not a specific domU.

Many thanks,

Joost