IO Delay

xadox

Active Member
Aug 21, 2019
40
3
28
I have always had the problem with repeatedly occurring IO delay increases up to 60% and more during heavy hard disk activity.
One of my LXCs is an SMB server and when I move large data back and forth over a long period of time, the problem usually occurs.

My specs are as follows:
  • 12 x AMD Ryzen 5 2600 Six-Core Processor
  • 64GB ECC RAM
  • OS on NVME
  • LXCs on NVME
  • Virtual Environment 8.2.4
  • 8x 3.5 HDD on Dell Perc/ LSI SAS2008 in JBOD
  • 2x RAIDZ1 20TB (4 discs) and 8TB (4 discs)
Do you have any suggestions for me as to where I might start?
 
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RAIDz1 has poor IOPS and is not very suitable for running guests on, which has been discussed several times before on this forum. Use enterprise SSDs in a stripes of mirrors (like RADI10) for better performance.

EDIT: Hardware RAID5 is also faster (but less features and checksums) than RAIDz1.

EDIT2: I got confused by the NVMe, but it does not seem to matter and I deleted my confused replies.
 
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I know, and because of that I think I read in the past that it would make more sense to use the zpool via MP.
Like in my case:
arch: amd64
cores: 4
hostname: smb
memory: 2048
mp0: /tank1/share,mp=/data
mp1: /tank1/backup,mp=/backup

The LXC itself is running from the NVME.
 
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Have to check. I do not remember what brand I put in. :D It has been in use for more or less 7 years.
But why does that matter? The pure LXC runs from the NVME and the IO load is on the RAIDZ1.
 
As I don't want to simply throw my setup overboard for cost reasons, I'm wondering what alternatives there are.
Can an ARC cache possibly bring improvements?
 
As I don't want to simply throw my setup overboard for cost reasons, I'm wondering what alternatives there are.
Can an ARC cache possibly bring improvements?
Change the RAIDz1 to a stripe of two mirrors (a in RAID10, which I suggested in my first reply)? RAIDz1 has a lot of padding (as also discussed before on this forum), so you might not even lose much space. Or use your hardware RAID controller instead of ZFS.
 

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