On Thu, 16 Jun 2016 15:19:22 +0530 Ritesh Raj Sarraf <[email protected]> wrote: > Control: tag -1 +pending > > On Wed, 2016-06-15 at 13:03 -0600, Andrew Patterson wrote: > > For most users this is not an issue. How many systems are going to use > > that many LUNs? > > > > I agree. > > > One counter-example is using one or more FC LUNs per VM guest on a > > host. In such a case, one can just modify /etc/sysctl.conf to increase > > the setting. > > Yes. Most hypervisors may want this. But again, like you said, most users do > not > map that many LUNs. And recommended practice is to have a VM backed by a file > backend mostly.
OpenStack/cinder can (and is) be uses to provision VMs with networked drives. It is pretty common for cloud applications. I don't know what a practical limit for the number of volume per VMs per host should be. > > > We can run into problems when using > > multipath-tools-boot. In this case, we use the default kernel settings > > for aio-max-nr since multipath is run from the initramfs. I have > > worked around this by modifying the script in > > /usr/share/initramfs/scripts/local-top/multipath to temporarilly set > > aio-max-nr to 1048576 while doing discovery. > > > So, I'll just add this to README.Debian. There's not much that we can do > beyond > documenting such behavior. I will work on patch to have a user-configurable setting of aio-max-nr in the initramfs. You can then decide if it is worth it to apply it. In the meantime, the README.Debian change sounds fine to me. -- Andrew Patterson Hewlett-Packard Enterprise
