Recent content by christian.g

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    VMs freezing and unreachable when backup server is slow

    For testing I added a special device (mirror of 2 256GB NVMe) to the pool on PBS site and did set the small files limit to 32k on the dataset. It helped a bit. I did get an overall backup speed of 100MiB/s. I will leave it added for now until a better solution is available. Warning: A special...
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    VMs freezing and unreachable when backup server is slow

    A Special Device is not a write cache but a "normal" vdev. Meaning, the data stays there and doesn't get flushed to the spinning disks. We need more something like bcache in front of the zfs pool but this introduces a complex setup and i personally think it would make way more sense to implement...
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    VMs freezing and unreachable when backup server is slow

    Not sure what you mean. ZFS doesn't have a Write Cache. SLOG is not a Write Cache.
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    VMs freezing and unreachable when backup server is slow

    Thanks but I suspect this will slow down backups and sounds more like a workaround. Why not implement a SSD/NVMe Write-Cache in PBS? Add a zpool of mirrored fast devices with enough capacity, write there then flush to spinning disks in background. That way one can have fast and save backups...
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    VMs freezing and unreachable when backup server is slow

    Any update on this? We have this problem on a regular basis and it's becoming a real show stopper.
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    VirtIO vs SCSI

    All of your points are valid but in the end the Cluster has to be fast enough to fit the needs and with Cache "None" it's not. I generally favor safety over performance but in this case the numbers are far to bad and users have to do their work without going to have a coffee until the...
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    VirtIO vs SCSI

    True but i would appreciate if instead of just saying "Not true" you would provide usable information. :) I wrongly interpreted the Discard Option! It is about thin provisioning and not about flash storage. "Disk images in Proxmox are sparse regardless of the image type, meaning the disk image...
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    VirtIO vs SCSI

    Sure, that's what writeback does. :) Ok, so the usual writeback drawbacks. Thanks. Yes, but this only applies to flash storage. I just wanted to point out that discard impacts performance. In my case i need discard but this does not automatically applies to others. I've tested on flash...
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    VMs freezing and unreachable when backup server is slow

    Till now a few suggestion have been provided by the community like - manually increase the memory buffer size - add a fast and large enough buffering device like a PCI NVMe or a ZFS mirror of them - use storage snapshots if available (ZFS/CEPH) - use backup fleecing Is Proxmox working on any...
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    VirtIO vs SCSI

    I know this is an old thread but i'm currently investigating IOPs on our Ceph cluster. Test VM Debian 10 (Kernel 4.19) Test Suite fio with 4k randrw test Every test was repeated 3 times First tests to raw rdb block devices from within the VM to identify the best BUS (SCSI vs Virtio) with no...
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    Ceph with multipath

    On my side everything is working flawless. Make sure your LVM config and HBA Drivers are setup right and included in the initramfs.
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    Ceph with multipath

    And in case someone needs a script to list OSDs with corresponding devices (incl. multipath and their member disks) as well as not used multipath devices. #!/bin/bash data=$(ceph-volume lvm list --format json) ar=($(echo $data | jq -r 'to_entries | sort_by(.key | tonumber) | map(.key + ":" +...
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    Ceph with multipath

    Btw, i changed my script a little bit. My multipath devices are named "mpathXX". If yours are named different, you need to change the script. #!/bin/bash DRYRUN=0 if [[ "$1" == "--dryrun" ]] then DRYRUN=1 fi readarray -t cdevs < <(ceph-volume lvm list | grep -o -E "/dev/mapper/mpath.*"...
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    Ceph with multipath

    Your missing the keyring See https://forum.proxmox.com/threads/unable-to-create-osds-in-new-proxmox-ceph-cluster-rados-object-not-found-error-connecting-to-the-cluster.78961/
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    VMs freezing and unreachable when backup server is slow

    We are having a hard time too. The combination of dirty maps in conjunction with a mid-fast PBS is giving us nightmares. We have > 40 VMs and also have a few VMs which are quite big database servers (>3TB). Sometimes they need updates and a reboot is required, which in turn invalidates the dirty...

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