Very Slow Read Performance from Array

[JPrez]

Hey All -

 

Still trialing out my unRaid build and seem to have run into an issue.   While I understand unRaid is slow to write files to the array (hence a cache disk) I was under the impression that read speeds were not affected.   On the same equipment I was getting 112mb/s down without an issue all night and day....however, with unRaid I'm lucky to get 5-7mb/s down.

 

I read several posts and did the common things, I checked the ethernet card and rate via ethtool:

 

 Advertised pause frame use: Symmetric
        Advertised auto-negotiation: Yes
        Speed: 1000Mb/s
        Duplex: Full
        Port: Twisted Pair
 

The device I'm using to pull files from the server is also connected via ethernet and with a gigabit link.   For testing, I was downloading a 20gig file from the server and the sustainted speed was around 5mb/s

 

Hardware wise, it's a SuperMicro SL7-F board with 8 (4TB) WD Red drives (6 in array, 2 for parity) and a SSD drive for cache.  32 Gigs of ECC ram and dual Intel NICs.

 

The parity is still undergoing a rebuild (about 30% complete since it's a new install) but that shouldn't affect the download from the server should it?

 

Thanks

 

 

[trurl]

Before rebooting, go to Tools - Diagnostics and post complete zip.

[JPrez]

53 minutes ago, trurl said:

Before rebooting, go to Tools - Diagnostics and post complete zip.

 

 

[JorgeB]

40 minutes ago, JPrez said:

The parity is still undergoing a rebuild (about 30% complete since it's a new install) but that shouldn't affect the download from the server should it?

Yes it will, and by a lot,  wait for the parity sync to finish.

[JPrez]

Thanks - I'll wait for the parity build to stop before trying again - about 3 days to complete apparently.

 

On a related note, would changing the Disk Settings -> md write method to "reconstruct write" help with write performance even with a cache SSD drive or should I remove and not use the cache drive with this feature turned on?

 

Thanks

[JorgeB]

10 minutes ago, JPrez said:

about 3 days to complete apparently.

That's way too long for 4TB, should be around 10 to 12H, make sure you're not using the disks and also change the default tunables to these, it should help:

 

Settings -> Disk Settings

Tunable (md_num_stripes): 4096
Tunable (md_sync_window): 2048
Tunable (md_sync_thresh): 2000

 

11 minutes ago, JPrez said:

would changing the Disk Settings -> md write method to "reconstruct write" help with write performance even with a cache SSD drive

It will help if you write directly to the array, not for the cache device.