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    Solved Alert: Control Domain Memory Usage

    Compute
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    • olivierlambert
      olivierlambert Vates 🪐 Co-Founder🦸 CEO 🧑‍💼 last edited by olivierlambert

      The latest report was on a NFS storage, however lsmod displays various iSCSI modules loaded. So it doesn't mean it's not an iSCSI module issue:

      scsi_mod              253952  13 fcoe,scsi_dh_emc,sd_mod,dm_multipath,scsi_dh_alua,scsi_transport_fc,libfc,bnx2fc,megaraid_sas,sg,scsi_dh_rdac,scsi_dh_hp_sw

      edit: what about bnx2fc? Is it common to other reports?

      edit 2: nope, might be megaraid_sas instead.

      stormi 1 Reply Last reply Reply Quote 0
      • olivierlambert
        olivierlambert Vates 🪐 Co-Founder🦸 CEO 🧑‍💼 last edited by

        Is there a way to provide alternate/up to date modules for the most suspicious ones? At some point, we'll find the culprit!

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        • stormi
          stormi Vates 🪐 XCP-ng Team 🚀 last edited by stormi

          It depends how self-contained the modules are. For device drivers, it's usually feasible. For more core parts of the kernel, I think we should rather try to identify patches that look like they could fix the issue and rebuild the kernel with them.

          We could also opt for a dichotomy approach between the main kernel and the alternate kernel, but since it takes days before one can be sure that there's no leak, it's not really doable, unless we find a way to reproduce the issue way faster (which is another thing in which users may help: try to provoke the memleak on purpose. High network load seems to be a lead.).

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          • stormi
            stormi Vates 🪐 XCP-ng Team 🚀 @olivierlambert last edited by stormi

            @olivierlambert said in Alert: Control Domain Memory Usage:

            The latest report was on a NFS storage, however lsmod displays various iSCSI modules loaded. So it doesn't mean it's not an iSCSI module issue:

            Isn't it SCSI rather than iSCSI here? However, maybe the leak is in SCSI layers indeed...

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

              I am seeing similar behavior with Citrix Hypervisor 8.2LTSR after upgrading from 7.1CU2, which was not affected. We have a pool with 5 Poweredge R730 hosts and 2 R720 hosts. All have Intel 10G and 1G NICs (ixgbe and igb drivers) and we use iSCSI storage. I have had two hosts use up all their control domain memory, requiring an evacuate/reboot of the host. One host was the pool master, which runs only one VM (xen orchestra appliance) but is generally busy with various iSCSI tasks due to snapshot coalesce after daily backups. The other host has ~20 VMs that are pretty busy with network activity. No userspace processes that seem to be using an abnormal amount of memory.

              1 Reply Last reply Reply Quote 2
              • stormi
                stormi Vates 🪐 XCP-ng Team 🚀 last edited by

                Thanks, this is good to have confirmation of what we thought about CH 8.2 but couldn't prove!

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                • F
                  fasterfourier @stormi last edited by

                  @stormi I've just opened a Citrix case on the issue, but I wouldn't expect much help there, and definitely wouldn't expect anything quickly.

                  stormi 1 Reply Last reply Reply Quote 0
                  • stormi
                    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.

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                    • F
                      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
                      • borzel
                        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
                        • borzel
                          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

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                          • borzel
                            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
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                            • R
                              r1 XCP-ng Team 🚀 @borzel last edited by

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

                              borzel 1 Reply Last reply Reply Quote 0
                              • borzel
                                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
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                                • R
                                  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?

                                  borzel 1 Reply Last reply Reply Quote 0
                                  • borzel
                                    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

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

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

                                      borzel 1 Reply Last reply Reply Quote 0
                                      • borzel
                                        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
                                        • borzel
                                          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
                                          • olivierlambert
                                            olivierlambert Vates 🪐 Co-Founder🦸 CEO 🧑‍💼 last edited by

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

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