On Tue 11 Mar 2014 11:32:37 AM Karsten Kruse wrote:
> Ahoi,
>
> i have a bunch of net6501-70 for evaluation and they show poor I/O
> performance.
>
> I use CentOS 6.5 with kernel 2.6.32-431.5.1.el6.x86_64 and this is my disk:
>
Linux firewall 3.12.0-rc3+ #3 SMP Mon Oct 21 17:15:52 MDT 2013 x86_64 GNU/Linux
I get about the same as you. My read speeds are higher, around 130MB/s, but
testing write speeds to my Crucial m4 gets me 20MB/s. I thought that was more
or less normal for the mSATA slots. Maybe I'm wrong though. I certainly would
expect that m4 card to get much higher than 20MB/s write on its own, so it
likely isn't the card that's slow. Specs say 260MB/s.
> [root@sonde04 ~]# hdparm -i /dev/sda
>
> /dev/sda:
>
> Model=Samsung SSD 840 EVO 120GB, FwRev=EXT0BB0Q, SerialNo=S1D5NSADB40689E
> Config={ Fixed }
> RawCHS=16383/16/63, TrkSize=0, SectSize=0, ECCbytes=0
> BuffType=unknown, BuffSize=unknown, MaxMultSect=16, MultSect=16
> CurCHS=16383/16/63, CurSects=16514064, LBA=yes, LBAsects=234441648
> IORDY=on/off, tPIO={min:120,w/IORDY:120}, tDMA={min:120,rec:120}
> PIO modes: pio0 pio1 pio2 pio3 pio4
> DMA modes: mdma0 mdma1 mdma2
> UDMA modes: udma0 udma1 udma2 udma3 udma4 udma5 *udma6
> AdvancedPM=no WriteCache=enabled
> Drive conforms to: unknown: ATA/ATAPI-2,3,4,5,6,7
>
> * signifies the current active mode
>
>
> Looks good to me, UDMA6 is used. This doesn't look as good:
>
>
> [root@sonde04 ~]# time dd if=/dev/sda of=/dev/null bs=1M count=1024
> 1024+0 Datensätze ein
> 1024+0 Datensätze aus
> 1073741824 Bytes (1,1 GB) kopiert, 14,0558 s, 76,4 MB/s
>
>
> So this is read, this is what write looks like:
>
>
> [root@sonde04 ~]# sync ; time { dd if=/dev/zero of=/tmp/test.dd bs=1M
> count=1024 ; sync ; }
> 1024+0 Datensätze ein
> 1024+0 Datensätze aus
> 1073741824 Bytes (1,1 GB) kopiert, 47,0048 s, 22,8 MB/s
>
> real 0m50.428s
> user 0m0.022s
> sys 0m7.021s
>
>
> This is 1 GB (power of 2) written in 50 seconds, so that amounts to
> about 20,5 MB/s. Would anyone be so kind and run the commands himself,
> maybe with Debian or something with a more recent kernel.
>
> Also i would appreciate any tips on how to get a bit more write
> performance. We would like to monitor traffic with it, using NtopNG and
> tcpdump. When we dump traffic, we don't write payloads, just headers, so
> we don't need more than maybe 40 MB/s guess.
>
>
> Have a nice day,
>
> Karsten Kruse
--
Thomas Fjellstrom
[email protected]
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