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BRU PE restore really sloooow at 13MB/s

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Tim v d Hoff
BRU PE restore really sloooow at 13MB/s
on Nov 13, 2017 at 11:41:32 am
Last Edited By Tim v d Hoff on Nov 13, 2017 at 12:11:14 pm

Hi all,

I've been a long time BRU PE user and am experiencing very slow restore performance lately, with the drive shoeshining at 13MB/s...

My machine is an iMac 27" 4Ghz 5K (late 2015) and HP Ultrium 3000 SAS LTO-5 drive, connected through an ATTO HBA680 in a Sonnett Echo Express II thunderbolt expansion chassis. I'm restoring to a QNAP TVS-871T 8-bay RAID-6 system using SMB3.

Previously, the RAID system was connected straight to my iMac using Thunderbolt bridge, giving me read/write speeds of approx. 600/800MB/s. BRU PE would run the drive at advertised speeds of around 140MB/s.

Now, my setup has changed slightly: instead of a straight thunderbolt connection, I'm using a SANlink2 10G ethernet adapter, using the same Thunderbolt port that was previously used for the thunderbolt bridge. Speeds are even higher at around 800/1100MB/s, yet when restoring it's stuck at a measely 13MB/s.

My current workaround is to restore locally to the iMac, which goes faster (but is limited by the internal drive speed) and then copy it over to the RAID system (which again is limited by the iMac drive speed). Needless to say, this is a PITA and shouldn't be necessary.

Seeing that basically it's just the Thunderbolt bridge that's replaced with a 10G ethernet adapter, I'm thinking the problem is related to this, but I'm at a loss as to what it could be exactly. Especially since the overall speed (tested with AJA test software) has improved.

Does anyone have a clue? Maybe Tim from Tolis?

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Tim Jones
Re: BRU PE restore really sloooow at 13MB/s
on Nov 13, 2017 at 10:52:51 pm

Have you disabled SpotLight and Timemachine on the drive? Also, have you verified that you're using the cifs:// protocol instead of the smb:// protocol? Apple's SMB2 protocol is problematic - especially when dealing for permissions and metadata which something that AJA and Black Magic Disk Speed Test don't do when checking speed.

Tim Jones
CTO - TOLIS Group, Inc.
BRU ... because it's the RESTORE that matters!

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Tim v d Hoff
Re: BRU PE restore really sloooow at 13MB/s
on Nov 17, 2017 at 2:02:34 pm
Last Edited By Tim v d Hoff on Nov 17, 2017 at 3:45:17 pm

Hi Tim,

Thanks for your message and sorry for the late reply!

I've not changed any parameters other than the ones I stated and I'm running SMB3.
Timemachine is not running and I had no idea that Spotlight could index NAS drives.
So, either it always interfered or it never did. Regardless, I disabled it.

Just to get some more insight on the matter, I've ran a test doing a backup and restore run with the same 40GB of video data (bunch of small MP4 plus three 10GB+ MXF files) on both my 'regular' SMB3 share, a manual connection using the CIFS:// protocol and my old and trusted NFS share that I used to work with prior to changing the setup.

You notice that the SMB share wins the AJA test, with the CIFS connection dragging miles behind. No good for video editing. (The write speed of the NFS share used to be much higher previously. Don't know what happened there.)

Next, all three perform backup tasks at roughly the same 120MB/s speed. SMB and NFS do so continuously (gap is between two big files), but CIFS fluctuates quite a bit.

Lastly, the restore job: all are much slower than the backup speed and NFS performs best, though none have a consistent output. SMB and CIFS are identical.

I know the restore can be much faster, because the tape drive runs at high speed continuously when restoring to my local drive.

What can this be?

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