Jump to content

Array write capped at 20MB/s


rik3k

Recommended Posts

I have a dual parity array with 27 data disks (29 drives total). I simply cannot get the write speed to the array to go above 20mb/s. When I write to a cache drive (without parity) I have no issues. Tried disabling dockers/VMs, even tried single parity and the result is the same. Swapped out HBA cards, tried SATA parity vs SAS. Result is always the same. Tried playing around with Tunables but there does not seem to be an impact.

 

Write caching enabled on all drives as well. Any thoughts?

 

 

sodium-diagnostics-20210825-0828.zip

Link to comment
14 minutes ago, JorgeB said:

Default writing mode with can be around that with older disks, you can try turbo write, but note that with so many disks you might run into a controller bottleneck, depends on the controller/enclosure you're using, it can never be faster than a parity check at any point.

 

Turbo write enbaled/disabled also makes no difference. Unless a reboot is required to enable?

 

Are you suggesting that perhaps I split the 'load' across multiple HBAs?

Link to comment
9 minutes ago, rik3k said:

Are you suggesting that perhaps I split the 'load' across multiple HBAs?

Might not be the HBA, could be the enclosure or the HBA link speed, you can see here typical results for various HBAs.

 

10 minutes ago, rik3k said:

Unless a reboot is required to enable?

It's not, what speed do you get during a parity check?

Link to comment
21 minutes ago, JorgeB said:

Might not be the HBA, could be the enclosure or the HBA link speed, you can see here typical results for various HBAs.

 

It's not, what speed do you get during a parity check?

 

Same 20MB/s during parity check. Writing to drives off parity-protected array gives me 150/160MB/s pretty consistently. 

 

I have a 2308 chipset HBA so I should be able to get much higher. It's really somehow tied to parity writes. CPU is barely touching 3% during transfers and plenty ram available.

 

I did see a lot of documentation on the tunables but these seemed to apply to previous versions of Unraid. Newer version have less parameters and they don't seem to make much of an impact.

Link to comment

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...