Very Low Harddrive Performance (10MB/s)

Steppi · 18. Dezember 2015

Hi,

I am into debugging a problem I have with my Hardrives in my OMV Box.

These Days when copying some bigger amount of data between the 2 internal SATA Harddrives of my OMV Box it came to my attention that the drives are extremely slow. During copying iotop/iostat reports a max throughput of 10MB/s from one local sata HDD to another local sata HDD.

Some background on my system:

MotherBoard: Asrock Q1900-ITX - 4MB Ram

Installed Volumes:
Systemvolume: SanDisk SDSSDP06 (/dev/sda)

2x Datavolumes: SAMSUNG HD105SI (no Raid, plain ext4 FS) (sdb, sdd)

as the motherboard does only habe 2 SATA ports, I use a SiI 3531 Serial ATA Controller on the 1xPCIe port of the MB for the second Data HDD.

I went through

http://forums.openmediavault.o…peed-tests-in-a-nutshell/
and done some of the proposed diagnosis:

Speed Measurements:

Code

root@omv:/media/78e8bd07-7143-481a-b938-232cd143c5b3/home/stephan/iospeed# hdparm -Tt /dev/sda


/dev/sda:
 Timing cached reads:   3186 MB in  2.00 seconds = 1593.37 MB/sec
 Timing buffered disk reads: 704 MB in  3.01 seconds = 234.25 MB/sec
root@omv:/media/78e8bd07-7143-481a-b938-232cd143c5b3/home/stephan/iospeed# hdparm -Tt /dev/sdb


/dev/sdb:
 Timing cached reads:   2878 MB in  2.00 seconds = 1439.26 MB/sec
 Timing buffered disk reads: 32 MB in  3.13 seconds =  10.23 MB/sec
root@omv:/media/78e8bd07-7143-481a-b938-232cd143c5b3/home/stephan/iospeed# hdparm -Tt /dev/sdd


/dev/sdd:
 Timing cached reads:   2980 MB in  2.00 seconds = 1490.47 MB/sec
 Timing buffered disk reads:  32 MB in  3.13 seconds =  10.24 MB/sec

Alles anzeigen

Code

root@omv:/media/78e8bd07-7143-481a-b938-232cd143c5b3/home/stephan/iospeed# dd if=/dev/sda of=/dev/null bs=100M count=3
3+0 Datensätze ein
3+0 Datensätze aus
314572800 Bytes (315 MB) kopiert, 1,23075 s, 256 MB/s
root@omv:/media/78e8bd07-7143-481a-b938-232cd143c5b3/home/stephan/iospeed# dd if=/dev/sdb of=/dev/null bs=100M count=3
3+0 Datensätze ein
3+0 Datensätze aus
314572800 Bytes (315 MB) kopiert, 29,2997 s, 10,7 MB/s
root@omv:/media/78e8bd07-7143-481a-b938-232cd143c5b3/home/stephan/iospeed# dd if=/dev/sdd of=/dev/null bs=100M count=3
3+0 Datensätze ein
3+0 Datensätze aus
314572800 Bytes (315 MB) kopiert, 29,3399 s, 10,7 MB/s
root@omv:/media/78e8bd07-7143-481a-b938-232cd143c5b3/home/stephan/iospeed#

Alles anzeigen

One can see immediately, that the read performance of the 2 HDDs is extremly lousy (10MB/s)

No Problem with the interface speeds:

Code

root@omv:/media/78e8bd07-7143-481a-b938-232cd143c5b3/home/stephan/iospeed# hdparm -I /dev/sdb | grep -i speed
           *    Gen1 signaling speed (1.5Gb/s)
           *    Gen2 signaling speed (3.0Gb/s)


root@omv:/media/78e8bd07-7143-481a-b938-232cd143c5b3/home/stephan/iospeed# hdparm -I /dev/sdd | grep -i speed
           *    Gen1 signaling speed (1.5Gb/s)
           *    Gen2 signaling speed (3.0Gb/s)

dmesg shows no obvious errors, however it contains some infromation I do not understand:

[ 3.669519] ata3: SATA link up 3.0 Gbps (SStatus 123 SControl 0) -> What means SControl 0, the other drives show SControl300

[ 3.675194] ata3.00: ATA-8: SAMSUNG HD105SI, 1AJ10001, max UDMA/133
[ 1.795547] ata2.00: ATA-8: SAMSUNG HD105SI, 1AJ10001, max UDMA/133
-> Why are both drives using ATA-8 even though one Drive is on the Motherboards "internal" SATA controller and one is on the PCIe to SATA Bridge ?
-> Why is ata2.00 using AA Mode and ata3.00 is not ?

Code

root@omv:/media/78e8bd07-7143-481a-b938-232cd143c5b3/home/stephan/iospeed# egrep 'ata[0-9]\.|SATA link up' /var/log/dmesg
[    1.781840] ata1: SATA link up 3.0 Gbps (SStatus 123 SControl 300)
[    1.782289] ata1.00: ATA-9: SanDisk SDSSDP064G, 3.2.0, max UDMA/133
[    1.782296] ata1.00: 123091920 sectors, multi 1: LBA48 NCQ (depth 31/32)
[    1.783159] ata1.00: configured for UDMA/133
[    1.789876] ata2: SATA link up 3.0 Gbps (SStatus 123 SControl 300)
[    1.795547] ata2.00: ATA-8: SAMSUNG HD105SI, 1AJ10001, max UDMA/133
[    1.795555] ata2.00: 1953525168 sectors, multi 16: LBA48 NCQ (depth 31/32), AA
[    1.801331] ata2.00: configured for UDMA/133
[    3.669519] ata3: SATA link up 3.0 Gbps (SStatus 123 SControl 0)
[    3.675194] ata3.00: ATA-8: SAMSUNG HD105SI, 1AJ10001, max UDMA/133
[    3.675201] ata3.00: 1953525168 sectors, multi 0: LBA48 NCQ (depth 31/32)
[    3.680934] ata3.00: configured for UDMA/100
[    8.045568] ata3.00: configured for UDMA/100
[    8.049395] ata2.00: configured for UDMA/133
[    9.127796] ata2.00: configured for UDMA/133
[    9.152149] ata3.00: configured for UDMA/100

Alles anzeigen

Does anyone have an Idea how to further track this issue down ?

Best Regards
Stephan

ryecoaaron · 18. Dezember 2015

Are you using the backports 3.16 kernel?

Steppi · 18. Dezember 2015

yes, forgot to mention.

Used Kernel: 3.16.0-0.bpo.4-586

ryecoaaron · 18. Dezember 2015

Why didn't you use the 64 bit install? Not sure why the speeds would be so slow otherwise.

Steppi · 18. Dezember 2015

actually by accident.

But why should a 32 bit install show slow HDD speeds ... sounds unrelated to me ... its a small box for which 3GB of memory should be plenty.

root@omv:/media/78e8bd07-7143-481a-b938-232cd143c5b3/home/stephan# free -h
total used free shared buffers cached
Mem: 2,7G 393M 2,3G 0B 24M 263M
-/+ buffers/cache: 106M 2,6G
Swap: 2,4G 0B 2,4G

ryecoaaron · 18. Dezember 2015

32 bit drivers may not be supported as well as 64 bit drivers especially in the case of a lesser used chipset like the Sil 3531. I would boot systemrescuecd with the 64 bit kernel and see if the speeds are low with that kernel. You could try the 32bit kernel on the same image as a test too.

Steppi · 18. Dezember 2015

Good point, will do !

subzero79 · 18. Dezember 2015

Check your bios, could be you have ide mode enabled instead of ahci for the SATA ports

Steppi · 18. Dezember 2015

oh my god so much better:

using systemrescuecd-x86-4.6.1.iso both drives serve @ 100MB/s straight.

I also tried the 32bit kernel from systemresuecd -> Same good performance.

I also tried to boot my current installation into maintenance mode using both available kernels

Debian GNU/Linux, with Linux 3.16.0-0.bpo.4-586
Debian GNU/Linux, with Linux 3.2.0-4-686-pae

and also tried to unmount the HDD before checking the performance

but no success ....

Next thing I do is download the 64bit omv image and try to live boot it and see whats the outcome.

Any other good ideas ?

Best Regards
s.

ryecoaaron · 18. Dezember 2015

I figured the newer kernel on systemrescuecd would help. You can't live boot the OMV installer ISO but you could download a 64bit Debian Wheezy livecd to test. Unfortunately, if the 64 bit kernel is slow too, you will need to compile drivers or a kernel to get the better speeds.

Steppi · 19. Dezember 2015

Hi,

@subzero79 - BIOS is set to AHCI Mode

@ryecoaaron

I have tried with a Debian Live CD called debian-live-7.9.0-amd64-rescue.iso

Code

# uname -a
Linux debian 3.2.0-4-amd64 #1 SMP Debian 3.2.68-1+deb7u3 x86_64 GNU/Linux

and the performance is perfect.

So it's likely, that teh 64 bit version of omv will do to, right ?

Next question would be: Can I use a saved configuration of a 32 bit OMV in order setup a 64bit omv ?

Best Regards
Steppi

subzero79 · 19. Dezember 2015

Zitat von Steppi

Can I use a saved configuration of a 32 bit OMV in order setup a 64bit omv ?

Just as a reference you can keep /etc/openmediavault/config.xml, there's not export/import feature. So you'll have to redo everything again.

Steppi · 21. Dezember 2015

Hi, I just wanted to give you an update on this topic:

On the 64 bit installation the performance is ok, at least on a fresh install), so it seems that I have to go the migration path ....

Best Regards
steppi

Steppi · 21. Dezember 2015

new update:

after restoring my old 32bit system from an image written just before checking the 64bit kernel performance the 32 bit system also shows >100Mbyte/s read performance.

I am confused ...

Best Regards
Steppi

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