Jump to content

[solved] Another why are my write speeds slow topic


rilles

Recommended Posts

Posted

I setup my unraid system years ago in the 4.x era with a AMD Sempron and a Asus M4A785-M motherboard, it served me well.

I was always pokey getting 20mbs per tops on writes (no cache drive)

 

Fast forward today I decided to give some life back into the old horse.  I replaced the file system with XFS from RFS and put a old 7200 drive in as a cache drive.  30mbs tops during read and write from my desktop PC on a 1GB wired network.

I replaced it with a SSD.. same speeds.

Parity check nets me 105mbs speeds on average across all drives and so do internal file copies.

hdparm test shows 110 for the spinning disks and 525 for the SSD.

Looked at the network, 1GB on the NIC and when I do a "iperf3" test between unraid and my PC it shows 993MBs transfer rates.. so it seems not a cable/NIC issue.

 

What could be causing the slow transfer speeds? I've dug through the forums and no dice. My NIC is not stuck at 100Mbs, my SSD doesn't need trim as I just put it in (but I did a trim anyways).

 

tower-diagnostics-20180207-1022.zip

Posted

Nothing jumps out, I suggest you run a write test directly on the server just to check it's not network or source computer related, copy the attached script to your flash drive, on the console/SSH use it like so:

 

/boot/write_speed_test.sh /mnt/cache/test.dat

 

write_speed_test.sh

Posted

flying at max (for sata2) speed.

 

writing 10240000000 bytes to: /mnt/cache/test.dat
895405+0 records in
895405+0 records out
916894720 bytes (917 MB, 874 MiB) copied, 5.00294 s, 183 MB/s
1751206+0 records in
1751206+0 records out
1793234944 bytes (1.8 GB, 1.7 GiB) copied, 10.0087 s, 179 MB/s
2510890+0 records in
2510890+0 records out
2571151360 bytes (2.6 GB, 2.4 GiB) copied, 15.0141 s, 171 MB/s
3284608+0 records in
3284607+0 records out
3363437568 bytes (3.4 GB, 3.1 GiB) copied, 20.0201 s, 168 MB/s
4097778+0 records in
4097778+0 records out
4196124672 bytes (4.2 GB, 3.9 GiB) copied, 25.0267 s, 168 MB/s
4940662+0 records in
4940662+0 records out
5059237888 bytes (5.1 GB, 4.7 GiB) copied, 30.0321 s, 168 MB/s
5805463+0 records in
5805463+0 records out
5944794112 bytes (5.9 GB, 5.5 GiB) copied, 35.0417 s, 170 MB/s
6550138+0 records in
6550138+0 records out
6707341312 bytes (6.7 GB, 6.2 GiB) copied, 40.228 s, 167 MB/s
7326005+0 records in
7326005+0 records out
7501829120 bytes (7.5 GB, 7.0 GiB) copied, 45.0555 s, 167 MB/s
8017442+0 records in
8017442+0 records out
8209860608 bytes (8.2 GB, 7.6 GiB) copied, 50.0618 s, 164 MB/s
8892727+0 records in
8892727+0 records out
9106152448 bytes (9.1 GB, 8.5 GiB) copied, 55.1078 s, 165 MB/s
9681401+0 records in
9681401+0 records out
9913754624 bytes (9.9 GB, 9.2 GiB) copied, 60.0755 s, 165 MB/s
10000000+0 records in
10000000+0 records out
10240000000 bytes (10 GB, 9.5 GiB) copied, 61.8616 s, 166 MB/s
write complete, syncing
removed '/mnt/cache/test.dat'

Posted

With a cache drive installed now, I transfer quite big uploads (> 30 GB) from my Dell XPS at over 90 Mbytes/sec constant.. without cache drive it was around 40-45 Mbyes/sec

 

XPS is quite fast machine, so there might be indeed a bottleneck at the source

Posted

Transferred from different desktops, laptops that had Ubuntu, Linux Mint, Windows7 and windows 10 - same result.

Transfering between the desktops resulted in 80MBs speeds.

definitely something on the unraid box.. be it hardware or a config setting.

 

next steps -- plug in a new nic and build a new unraid box from junk parts to see if I can replicate the issue.

 

Posted
2 hours ago, rilles said:

definitely something on the unraid box.. be it hardware or a config setting.

The only thing that can be is the NIC, despite the iperf results, nothing else makes sense if the write speed test was normal, unless the share you're using wasn't writing to the cache device.

Posted

progress! sorta.  after a night of extreme testing I have found the real problem - hopefully the solution is easy.

 

On my main PC which is Linux Mint, samba transfers seem capped at 30MBs to/from unraid

If I mount a NFS share - then 101Mbs to/from unraid

If I use a Windows 10 machine, samba transfers are 101MBs to/from unraid

Thanks to the Win10 transfer graph I can see Mint -> Win10 transfers start at 90MBs then drop to 30MBs after 60% of the file for a 6GB file.

 

--> What could be causing Mint (Ubuntu 16.04 based) to have network throttling issues with samba?

 

Posted
7 minutes ago, rilles said:

What could be causing Mint (Ubuntu 16.04 based) to have network throttling issues with samba?

Like I suspected, source computer related, as for the issue, no idea, best bet would be to google ubuntu/mint slow smb,

Posted

sigh.. doesn't seem to be a Linux OS issue.. the file manager seems to be the issue.  Nemo/Nautilus file manager uses GVFS when it mounts a smb share.

GVFS mounts seem brutally slow, no fix for this bug that I can find.

https://github.com/linuxmint/nemo/issues/1304

https://bugs.launchpad.net/ubuntu/+source/gvfs/+bug/1236619

https://www.bountysource.com/issues/47919367-large-file-throughput-via-gvfs-smb-is-over-2x-slower-than-smbclient-or-fstab-mount-cifs

 

I guess if I have a lot of files to copy I can cifs mount it explicitly which apparently doesn't have the speed issue.

 

Posted

Check to see if you have the latest NIC drivers on the Mint computer. 

 

I had a Win7 machine with a RealTek NIC that much the same issues.  Updating the driver fixed it.  I know that RealTek drivers have been a big issue in Linux for years.  If you have a NIC with a brand of controller (Preferably Intel), I would try that one. 

Posted

Its a H270 kabylake motherboard with built in Intel NIC.  Its does not appear to be the NIC or any hardware, its an issue with a certain Linux smb storage interface (GVFS) that the file manager uses to mount smb shares.  The GVFS developers don't think is important enough to spend time fixing it.  NFS or an explicit "mount -t cifs ...." nets me 100MBs transfer speeds.

 

I guess unraid users are heavily Windows client based, I didn't find anything here about this from searching.

 

Posted
2 minutes ago, rilles said:

I guess unraid users are heavily Windows client based, I didn't find anything here about this from searching.

 

My observation is that is a true statement with the Mac OS being in the second place.  Of course, there are a lot of folks who are using media players and virtually all of them are Linux based BUT 100Mbps is more than adequate for all video streams.  

Archived

This topic is now archived and is closed to further replies.

×
×
  • Create New...