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Very Slow SMB performance

Very Slow SMB performance
« on: April 28, 2015, 05:40:02 PM »
Have a sme 8 server on i7 8 gig of ram.
All has been grand but smb performance to windows 7 desktops has slowed to about 1Mb /s
I have done an internet speed test and it tested at 77 Mb /s down so im sure the switch, cable nic etc are ok.
I have also copied a file on the machine disk to disk using mc on putty and it said 48 Mb/s to copy a 600Mb ISO file

Any suggestions on where to look?


Offline Daniel B.

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    • Firewall Services, la sécurité des réseaux
Re: Very Slow SMB performance
« Reply #1 on: April 28, 2015, 06:05:11 PM »
You have to find the bottleneck

- is the latency from workstation to server OK (and more or less constant)
- is the server swapping ?
- is the server busy with I/O ? You can install sysstat and check with something like "iostat -dm /dev/sda 1" which will show you I/O on sda every seconds
- is the CPU busy ? And what about the load. You can check both with htop
C'est la fin du monde !!! :lol:

Re: Very Slow SMB performance
« Reply #2 on: April 28, 2015, 11:23:17 PM »
Yes server load is less than .3 mostly at 99% idle. I assumed switch issue but speed test of internet showed cable and switch ok. Hard drives can handle 50ish meg as the hd copy file showed.
Its happened last week and a reboot seemed to solve the speed issue.

Re: Very Slow SMB performance
« Reply #3 on: May 02, 2015, 03:35:25 PM »
I should add that a reboot previously fixed it but not now.

Offline Jáder

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    • LinuxFacil
Re: Very Slow SMB performance
« Reply #4 on: May 03, 2015, 01:09:08 PM »
Try to diagnose your disk throughput with:
hdparm -tT /dev/sda

HEre are mine results (your's should be greater than 3000 MB/s if you're using modern motherboard/disks:

Code: [Select]
root@leopardo ~]# hdparm -tT /dev/sda

/dev/sda:
 Timing cached reads:   5564 MB in  2.00 seconds = 2785.03 MB/sec
 Timing buffered disk reads:  280 MB in  3.03 seconds =  92.48 MB/sec
[root@leopardo
...

Re: Very Slow SMB performance
« Reply #5 on: May 04, 2015, 03:22:24 PM »
1840.70 and 96.40

So not over 3000