Hot answers tagged

4

Modern OS and filesystem are much more resilient against corruption, and the same can be said for MySQL (especially when used with InnoDB tables). Basically, anything written to disk with sync/fsync semantic should be crash-safe, as the writes will not return until the data are on stable storage. Moreover, InnoDB uses internal journaling to be sure no ...


3

Is there any impact on performance from a kvm guest if I create ext4 on this large drive directly, mount it up on the host like /mnt/kvms and then create raw kvm disk image on it? Every time, when your data have more layers to go through performance degradation and latency increase will appear. For example: Qemu RAW file -> Ext4 -> LVM -> RAID1 device -...


2

Qemu takes VMs into pause on io errors by design, so that you will avoid corrupt disks. All you have to do is restore the iscsi connections and run/unpause the VMs


1

While it is interesting that nothing is showing up in netstat, you could attack this problem from a different angle. If something is sending 300 MB/s it will most likely be chewing up a decent amount of CPU ... try running top and based on the services that are using the most CPU check logs accordingly.


1

Edit: Even after the switch got power again and the storage was available, the VM's were still in an unresponsive crashed state. They did not react to any input whatsoever forcing me to do a hard-reset one by one, relying on the filesystem journaling to repair the damage. I was lucky it worked and nothing borked. As far as I understand, I got lucky there as ...


1

Recent libvirt/kvm versions support the discard vdisc option (for SCSI vdisk type only). With this option enabled, you can issue fstrim / on the guest fileststem and unused blocks will be immediately discarded by the host vm image, compacting/reducing it via hole punching. See here (driver section, search for 'discard') and here for more information. If ...


1

For the original poster, have you tried X2Go? I know that's another server piece you have to install in your 16.04 system, but using that on my machines, with the X2go client allowed multiple users to login with different X sessions at the same time. I find that depending on your hardware capabilities, the Mate and XFCE desktops perform really well. ...


1

Often when something reboots sporadically, it is not the OS, it is a physical problem. I'd start with the power supply. It is a good one, or cheap? Is there redundant power on the server, or is it a low-end server or desktop. Is the power overloaded? It is possible that there are a bunch of disks and those disks all spin and seek when doing backups ...


1

Cumulus Networks has upstreamed their patch to set the speed on the virtio_net driver. It is useful in network simulations with their Cumulus VX VM product. Patch is in Ubuntu Xenial. not sure if it is in Fedora today. More details can be found here. https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1581132 Another reference is my blog post about why ...


1

It seems working fine post Kilo release and newly downloaded images in qcow2 format. Flavor which I'm using 2CPU, 4GB RAM, 0 diskspace



Only top voted, non community-wiki answers of a minimum length are eligible