N5200 PRO read/write speed to disk is bad!

[jjussi]

Hi!
I have N5200 PRO with 5x1TB, RAID 5, 2x1GB ethernet (802.3a).
iPERF says that speed between HTPC and N5200 is 718 Mbit/sec, but when reading and/or writing data I can reach 20MB/s at peak and 9MB/s for average (when transfer of data is more than few seconds).
That's generate problems because if I read/write data from NAS in one thread, other threads (even they have high priority; HTPC is linux machine) have problems to write fast enought.. (I get ringbuffer overflows)

So, what I should do to make this N5200 write/read data faster from/to disks?

[jjussi]

Answering to my self.. It seems that I cannot do anything.. I tested (via SSH) drivers speed:

root@127.0.0.1:~# hdparm -T /dev/sda

/dev/sda:
Timing cached reads: 1836 MB in 2.00 seconds = 917.94 MB/sec
root@127.0.0.1:~# hdparm -t /dev/sda

/dev/sda:
Timing buffered disk reads: 138 MB in 3.02 seconds = 45.69 MB/sec
root@127.0.0.1:~# hdparm -T /dev/md0

/dev/md0:
Timing cached reads: 1936 MB in 2.00 seconds = 967.94 MB/sec
root@127.0.0.1:~# hdparm -t /dev/md0

/dev/md0:
Timing buffered disk reads: 118 MB in 3.00 seconds = 39.33 MB/sec

So.. If I cannot read from individual disk (or RAID) more than ~40 MB/sec.. Then there is something wrong!!!

[_DT]

You didn't mention what sort of disks you had. I have 5x WD7500AAKS-00RBA in my N5200PRO w/ Firmware 2.00.12. My hdparm numbers come out at nearly double yours for non-cached I/O though so it's possible the choice of disks is making the difference...

root@127.0.0.1:~# hdparm -T /dev/sda
/dev/sda:
Timing cached reads: 2080 MB in 2.00 seconds = 1039.94 MB/sec

root@127.0.0.1:~# hdparm -t /dev/sda
/dev/sda:
Timing buffered disk reads: 220 MB in 3.01 seconds = 73.13 MB/sec

root@127.0.0.1:~# hdparm -T /dev/md0
/dev/md0:
Timing cached reads: 2080 MB in 2.00 seconds = 1039.94 MB/sec

root@127.0.0.1:~# hdparm -t /dev/md0
/dev/md0:
Timing buffered disk reads: 240 MB in 3.01 seconds = 79.78 MB/sec

[jjussi]

You didn't mention what sort of disks you had. I have 5x WD7500AAKS-00RBA in my N5200PRO w/ Firmware 2.00.12. My hdparm numbers come out at nearly double yours for non-cached I/O though so it's possible the choice of disks is making the difference...

Hi!
I have those (not so famous) Samsung Spinpoint F1 HD103UJ disks and "Firmware Version 2.00.12"
Speed readings what I get, variates quite much.. And are always bigger what I get thru network protocol. I know! If I would use some other RAID level than 5, I would probably have higher thruput. RAID 0 would be (I think) fastest, but...

[_DT]

Hi,

I should have also said that I'm using RAID-6 rather than RAID-5 ... in theory RAID-6 has to do more parity calculations and so might be slower dependant upon what else is running on the N5200.

Do you have lots of modules installed that might be slowing things down?