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    Alert: Control Domain Memory Usage

    Scheduled Pinned Locked Moved Solved Compute
    194 Posts 21 Posters 200.6k Views 16 Watching
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    • stormiS Offline
      stormi Vates 🪐 XCP-ng Team @fasterfourier
      last edited by

      @fasterfourier Well, we've also tried to make the issue known to Citrix before so maybe your confirmation that it does not only happen in XCP-ng will be enough to trigger some movement about it. A memory leak that makes the host unusable is not a small issue.

      F 1 Reply Last reply Reply Quote 0
      • F Offline
        fasterfourier @stormi
        last edited by fasterfourier

        @stormi The ID for the case I just opened is 80240347. If you have a bugtracker issue open, you may want to mention that ticket. I just now opened the ticket, though, so it will be a while before it makes its way out of tier 1, etc.

        EDIT: Had the wrong case number at first. Updated case number.

        1 Reply Last reply Reply Quote 1
        • borzelB Offline
          borzel XCP-ng Center Team
          last edited by borzel

          We also have an issue with growing control domain memory:

          • XCP-ng 8.2
          • NFS shared storage
          • the poolmaster (xen19 is one of them) are more affected than pool members

          d1fac6d1-997b-4a7c-898c-d4a9c398b566-grafik.png

          Today I install the alternate kernel on one of our poolmaster to see if that resolves our issue.

          1 Reply Last reply Reply Quote 0
          • borzelB Offline
            borzel XCP-ng Center Team
            last edited by

            I noticed in my monitoring graphs, that since we have this issue, the SWAP is not used like before the issue:

            b07111c8-7c21-4351-85fa-2acc7030bb2d-grafik.png

            1 Reply Last reply Reply Quote 0
            • borzelB Offline
              borzel XCP-ng Center Team
              last edited by

              looked in my yum.log on this server (xen19):

              our problems startet exactly since "Apr 10 18:10:29 Installed: kernel-4.19.19-6.0.10.1.xcpng8.1.x86_64"

              yum.log.4.gz:Oct 03 17:35:54 Installed: kernel-4.4.52-4.0.7.1.x86_64
              yum.log.4.gz:Nov 20 18:29:29 Updated: kernel-4.4.52-4.0.12.x86_64
              yum.log.2.gz:Oct 10 20:19:31 Updated: kernel-4.4.52-4.0.13.x86_64
              yum.log.1:Apr 10 18:10:29 Installed: kernel-4.19.19-6.0.10.1.xcpng8.1.x86_64
              yum.log.1:Jul 07 17:46:34 Updated: kernel-4.19.19-6.0.11.1.xcpng8.1.x86_64
              yum.log.1:Dec 10 17:59:07 Updated: kernel-4.19.19-6.0.12.1.xcpng8.1.x86_64
              yum.log.1:Dec 19 13:53:39 Updated: kernel-4.19.19-6.0.13.1.xcpng8.1.x86_64
              yum.log.1:Dec 19 13:55:20 Updated: kernel-4.19.19-7.0.9.1.xcpng8.2.x86_64
              yum.log:Jan 18 17:35:07 Installed: kernel-alt-4.19.142-1.xcpng8.2.x86_64
              
              R 1 Reply Last reply Reply Quote 0
              • R Offline
                r1 XCP-ng Team @borzel
                last edited by

                @borzel How frequently do you restart VMs? And what's the last dom-id? # xl list

                borzelB 1 Reply Last reply Reply Quote 0
                • borzelB Offline
                  borzel XCP-ng Center Team @r1
                  last edited by borzel

                  @r1 in general we do not restart many of our VMs, its all very static, only manual operated

                  xen19 is now rebootet (we need it in production) with kernel-alt - highest id is currently 4

                  xen22 (pool master of another affected pool) - highest id is curently 30

                  memory graphs of xen22
                  61ef0b14-6ec2-46ea-96e6-6efbd30eb528-grafik.png

                  yum.log of xen22 (Problem here also after installing kernel-4.19.19-6.0.10.1.xcpng8.1.x86_64)

                  yum.log.5.gz:Dec 19 00:52:47 Updated: kernel-4.4.52-4.0.12.x86_6
                  yum.log.3.gz:Nov 08 10:07:40 Updated: kernel-4.4.52-4.0.13.x86_64
                  yum.log.1:Apr 10 20:31:01 Installed: kernel-4.19.19-6.0.10.1.xcpng8.1.x86_64
                  yum.log.1:Aug 31 23:10:50 Updated: kernel-4.19.19-6.0.11.1.xcpng8.1.x86_64
                  yum.log.1:Dec 11 18:00:54 Updated: kernel-4.19.19-6.0.12.1.xcpng8.1.x86_64
                  yum.log.1:Dec 19 12:52:00 Updated: kernel-4.19.19-6.0.13.1.xcpng8.1.x86_64
                  yum.log.1:Dec 19 12:54:13 Updated: kernel-4.19.19-7.0.9.1.xcpng8.2.x86_64
                  
                  R 1 Reply Last reply Reply Quote 0
                  • R Offline
                    r1 XCP-ng Team @borzel
                    last edited by

                    @borzel Between 4.19.19-6.0.9 to 4.19.19-6.0.10, following two patches were added.

                    0001-block-cleanup-__blkdev_issue_discard.patch
                    0001-block-fix-32-bit-overflow-in-__blkdev_issue_discard.patch
                    

                    Both are well vetted and seems stable without any further changes in them. Was there anything else updated along with kernel?

                    borzelB 1 Reply Last reply Reply Quote 0
                    • borzelB Offline
                      borzel XCP-ng Center Team @r1
                      last edited by borzel

                      @r1 yes, ever line "installed" in yum.log is an Upgrade from XCP-ng.
                      Problems started with XCP-ng 8.x

                      stormiS 1 Reply Last reply Reply Quote 0
                      • stormiS Offline
                        stormi Vates 🪐 XCP-ng Team @borzel
                        last edited by

                        @borzel did you "yum upgrade" from 7.x from 8.x?

                        borzelB 1 Reply Last reply Reply Quote 0
                        • borzelB Offline
                          borzel XCP-ng Center Team @stormi
                          last edited by

                          @stormi on server xen19 I think so, on server xen22 I'm not sure

                          I looked more close on my memory graphs and saw, that the memory baseline increases every night:

                          "bump" every day:
                          ca76f2fc-89aa-49fb-aa33-5e568070fbc4-grafik.png

                          closer look in week 53:
                          692a8c57-f2b5-4284-8cab-be3a045fb179-grafik.png

                          Dez 31. - Jan 01.
                          8a267bb0-97c3-481c-9da9-bd031093496e-grafik.png

                          Our Backups run from 18.00 till 3 or 4 in the morning (including coalesce).

                          --> maybe the heavy IO load leads to memory leaks "somewhere"?

                          1 Reply Last reply Reply Quote 1
                          • borzelB Offline
                            borzel XCP-ng Center Team
                            last edited by

                            Good news from the kernel-alt (server xen19): No RAM leaks so far 🙂

                            b6ca8f80-8bef-4dfe-9064-5823f6aba907-grafik.png

                            R 1 Reply Last reply Reply Quote 1
                            • olivierlambertO Offline
                              olivierlambert Vates 🪐 Co-Founder CEO
                              last edited by

                              At least that's consistent 🙂 Thanks for the feedback @borzel

                              1 Reply Last reply Reply Quote 0
                              • stormiS Offline
                                stormi Vates 🪐 XCP-ng Team
                                last edited by

                                @borzel yum upgrade from 7.x to 8.x is not supported, so it's likely that your host isn't in a perfectly clean state.

                                This is unrelated to the memory leak, but could cause other kinds of issues. Basically, scripts that should have run during the RPM upgrade to ensure the final state is consistent with what you'd have from an ISO upgrade either don't exist or haven't been tested.

                                borzelB 1 Reply Last reply Reply Quote 0
                                • borzelB Offline
                                  borzel XCP-ng Center Team @stormi
                                  last edited by

                                  @stormi I'm not complete sure if I did the iso upgrade or not... 😕

                                  But it's a good idea to reinstall the poolmaster from scratch...

                                  1 Reply Last reply Reply Quote 0
                                  • R Offline
                                    r1 XCP-ng Team @borzel
                                    last edited by

                                    @borzel I wish comparing kernel-alt and base kernel was easy to catch this... I'm sure that the tapdisk IO code is same in kernel and kernel-alt.

                                    Also the 2 patches mentioned earlier are also present in base kernel of xcp-ng 8.2 as well as kernel-alt 4.19.142. They are also present for xcp-ng 8.1 base kernel, however they are not present in xcp-ng 8.1 kernel-alt.

                                    Can you confirm your kernel-alt version?

                                    R borzelB 2 Replies Last reply Reply Quote 0
                                    • R Offline
                                      r1 XCP-ng Team @r1
                                      last edited by

                                      @borzel Also, I somehow need to be able to reproduce the issue at lab. If you can give more details about how do you do backup, may be I can simulate something.

                                      F borzelB 2 Replies Last reply Reply Quote 0
                                      • F Offline
                                        fasterfourier @r1
                                        last edited by

                                        @r1 If it helps at all, I have seen this more often on the pool master than in other pool hosts. We are using XO delta backup on 125 VMs in this pool daily. So, the master is busy doing a lot of snapshot coalesce operations (lots of iSCSI storage IO) compared to other hosts. The other host that has hit 95% control domain memory use is also IO heavy (it has some database server VMs).

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                                        • borzelB Offline
                                          borzel XCP-ng Center Team @r1
                                          last edited by borzel

                                          @r1 our complete setup:

                                          [FreeNAS NFS] <----shared-storage----> [Pool of 2 servers (xen22 + xen23)] ----XAPI---> [XO from sources] -----remote----> [FreeNAS NFS]

                                          All [servers] are real hardware servers, no VMs involved.

                                          Same chain of servers for xen19, execpt there are more pool members (and VMs).

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                                          • borzelB Offline
                                            borzel XCP-ng Center Team @r1
                                            last edited by borzel

                                            @r1

                                            [02:27 xen19 ~]# uname -a
                                            Linux xen19 4.19.142 #1 SMP Tue Nov 3 11:27:36 CET 2020 x86_64 x86_64 x86_64 GNU/Linux
                                            
                                            [02:30 xen19 ~]# yum list installed | grep kernel
                                            kernel.x86_64                   4.19.19-7.0.9.1.xcpng8.2    @xcp-ng-updates     
                                            kernel-alt.x86_64               4.19.142-1.xcpng8.2         @xcp-ng-base 
                                            

                                            memory graph so far:

                                            ca10cb2d-fbfb-48b0-8edd-237fc56ff38f-grafik.png

                                            looking very good!!!

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