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vm:proxmox:pbs:performance [2023/04/25 09:13] – niziakvm:proxmox:pbs:performance [2025/01/09 09:07] (current) – niziak
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 ====== performance ====== ====== performance ======
 +
 +===== FS tuning =====
 +
 +PBS stores everything in files. Maximum file size is 4MB.
 +  * Block device backup is in 4MB chunks
 +  * File backup chunk varies from 64kB to 4MB
 +
 +Filesystems:
 +  * ZFS 
 +    * [[https://pbs.proxmox.com/docs/sysadmin.html#zfs-special-device|special device]]
 +    * 128kB recordsize can cause write amplification for chinks smaller than 128kB
 +    * larger recordsize = less IOPS
 +    * Create histogram from existing PBS chunks sizes.
 +
  
 <code> <code>
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   * Use DRAID - where groups of stripes are used by design.   * Use DRAID - where groups of stripes are used by design.
   * Use at least separate ZFS dataset for backup, then set block size to <code bash>zfs set recordsize=1M YourPoolName/DatasetUsedAsDatastore</code>   * Use at least separate ZFS dataset for backup, then set block size to <code bash>zfs set recordsize=1M YourPoolName/DatasetUsedAsDatastore</code>
 +  * Disable atime <code bash>zfs set atime=off backup2</code>
 +
 +
  
  
 +Don't use a raidz1/2/3 as PBS needs high IOPS performance and IOPS performance will only scale with the number of striped vdevs, not with the number of disks. So 20 disks in a raidz wouldn't be faster than a single HDD.
 +And resilvering would also take forever.