Hello, We are using NFS storage. It is actually native NFS mounts on a NetApp storage system. We haven't seen those log entries, but we also don't always know when a VM gets corrupted... When we finally get a call that a VM is having issues, we've found that it was corrupted a while ago.
-----Original Message----- From: cloudstack-fan [mailto:cloudstack-...@protonmail.com.INVALID] Sent: Sunday, January 27, 2019 1:45 PM To: us...@cloudstack.apache.org Cc: dev@cloudstack.apache.org Subject: Re: Snapshots on KVM corrupting disk images Hello Sean, It seems that you've encountered the same issue that I've been facing during the last 5-6 years of using ACS with KVM hosts (see this thread, if you're interested in additional details: https://mail-archives.apache.org/mod_mbox/cloudstack-users/201807.mbox/browser). I'd like to state that creating snapshots of a running virtual machine is a bit risky. I've implemented some workarounds in my environment, but I'm still not sure that they are 100% effective. I have a couple of questions, if you don't mind. What kind of storage do you use, if it's not a secret? Does you storage use XFS as a filesystem? Did you see something like this in your log-files? [***.***] XFS: qemu-kvm(***) possible memory allocation deadlock size 65552 in kmem_realloc (mode:0x250) [***.***] XFS: qemu-kvm(***) possible memory allocation deadlock size 65552 in kmem_realloc (mode:0x250) [***.***] XFS: qemu-kvm(***) possible memory allocation deadlock size 65552 in kmem_realloc (mode:0x250) Did you see any unusual messages in your log-file when the disaster happened? I hope, things will be well. Wish you good luck and all the best! ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐ On Tuesday, 22 January 2019 18:30, Sean Lair <sl...@ippathways.com> wrote: > Hi all, > > We had some instances where VM disks are becoming corrupted when using KVM > snapshots. We are running CloudStack 4.9.3 with KVM on CentOS 7. > > The first time was when someone mass-enabled scheduled snapshots on a lot of > large number VMs and secondary storage filled up. We had to restore all those > VM disks... But believed it was just our fault with letting secondary storage > fill up. > > Today we had an instance where a snapshot failed and now the disk image is > corrupted and the VM can't boot. here is the output of some commands: > > ---------------------------------------------------------------------- > ---------------------------------------------------------------------- > ---------------------------------------------------------------------- > ---------------------------------------------------------------------- > ---------------------------------------------------------------------- > ---------------------------------------------------------------------- > ---------------------------------------------------------------------- > ------------------------------------------------ > > [root@cloudkvm02 c3be0ae5-2248-3ed6-a0c7-acffe25cc8d3]# qemu-img check > ./184aa458-9d4b-4c1b-a3c6-23d28ea28e80 > qemu-img: Could not open './184aa458-9d4b-4c1b-a3c6-23d28ea28e80': > Could not read snapshots: File too large > > [root@cloudkvm02 c3be0ae5-2248-3ed6-a0c7-acffe25cc8d3]# qemu-img info > ./184aa458-9d4b-4c1b-a3c6-23d28ea28e80 > qemu-img: Could not open './184aa458-9d4b-4c1b-a3c6-23d28ea28e80': > Could not read snapshots: File too large > > [root@cloudkvm02 c3be0ae5-2248-3ed6-a0c7-acffe25cc8d3]# ls -lh > ./184aa458-9d4b-4c1b-a3c6-23d28ea28e80 > -rw-r--r--. 1 root root 73G Jan 22 11:04 > ./184aa458-9d4b-4c1b-a3c6-23d28ea28e80 > > ---------------------------------------------------------------------- > ---------------------------------------------------------------------- > ---------------------------------------------------------------------- > ---------------------------------------------------------------------- > ---------------------------------------------------------------------- > ---------------------------------------------------------------------- > ---------------------------------------------------------------------- > ---------------------------------------------------------------------- > ----------------------------------------------------------- > > We tried restoring to before the snapshot failure, but still have strange > errors: > > ---------------------------------------------------------------------- > -------------- > > [root@cloudkvm02 c3be0ae5-2248-3ed6-a0c7-acffe25cc8d3]# ls -lh > ./184aa458-9d4b-4c1b-a3c6-23d28ea28e80 > -rw-r--r--. 1 root root 73G Jan 22 11:04 > ./184aa458-9d4b-4c1b-a3c6-23d28ea28e80 > > [root@cloudkvm02 c3be0ae5-2248-3ed6-a0c7-acffe25cc8d3]# qemu-img info > ./184aa458-9d4b-4c1b-a3c6-23d28ea28e80 > image: ./184aa458-9d4b-4c1b-a3c6-23d28ea28e80 > file format: qcow2 > virtual size: 50G (53687091200 bytes) > disk size: 73G > cluster_size: 65536 > Snapshot list: > ID TAG VM SIZE DATE VM CLOCK > 1 a8fdf99f-8219-4032-a9c8-87a6e09e7f95 3.7G 2018-12-23 11:01:43 > 3099:35:55.242 > 2 b4d74338-b0e3-4eeb-8bf8-41f6f75d9abd 3.8G 2019-01-06 11:03:16 > 3431:52:23.942 Format specific information: > compat: 1.1 > lazy refcounts: false > > [root@cloudkvm02 c3be0ae5-2248-3ed6-a0c7-acffe25cc8d3]# qemu-img check > ./184aa458-9d4b-4c1b-a3c6-23d28ea28e80 > tcmalloc: large alloc 1539750010880 bytes == (nil) @ 0x7fb9cbbf7bf3 > 0x7fb9cbc19488 0x7fb9cb71dc56 0x55d16ddf1c77 0x55d16ddf1edc 0x55d16ddf2541 > 0x55d16ddf465e 0x55d16ddf8ad1 0x55d16de336db 0x55d16de373e6 0x7fb9c63a3c05 > 0x55d16ddd9f7d No errors were found on the image. > > [root@cloudkvm02 c3be0ae5-2248-3ed6-a0c7-acffe25cc8d3]# qemu-img > snapshot -l ./184aa458-9d4b-4c1b-a3c6-23d28ea28e80 > Snapshot list: > ID TAG VM SIZE DATE VM CLOCK > 1 a8fdf99f-8219-4032-a9c8-87a6e09e7f95 3.7G 2018-12-23 11:01:43 > 3099:35:55.242 > 2 b4d74338-b0e3-4eeb-8bf8-41f6f75d9abd 3.8G 2019-01-06 11:03:16 > 3431:52:23.942 > > ---------------------------------------------------------------------- > ---------------------------------------------------------------------- > ---------------------------------------------------------------------- > ---------------------------------------------------------------------- > ---------------------------------------------------------------------- > ---------------------------------------------------------------------- > ---------------------------------------------------------------------- > ---------------------------------------------------------------------- > ---------------------------------------------------------------------- > ---------------------------------------------------------------------- > ---------------------------------------------------------------------- > ---------------------------------------------------------------------- > ---------------------------------------------------------------------- > ---------------------------------------------------------------------- > ---------------------------------------------------------------------- > ---------------------------------------------------------------------- > ---------------------------------------------------------------------- > ---------------------------------------------------------------------- > ---------------------------------------------------------------------- > --------------------------------------------------------------- > > Everyone is now extremely hesitant to use snapshots in KVM.... We tried > deleting the snapshots in the restored disk image, but it errors out... > > Does anyone else have issues with KVM snapshots? We are considering just > disabling this functionality now... > > Thanks > Sean
