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:
[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
--
Karsten Kruse
System Engineer Unix/Linux
Operation Center Infrastructure
Telefon: +49 (0) 2102 - 852 - 4335 (- 202 Fax)
[email protected]
http://www.qits.de/
QITS GmbH, Halskestraße 11-15 - 40880 Ratingen
______________________________________________
Geschäftsführer: Martin Giebel, Bernd Salz
Handelsregister: AG Düsseldorf HRB 44009
Ust.ID.-Nr.: DE 196843119 - Steuer-Nr.: 147/5761/047
0x35DBCAEC.asc
Description: application/pgp-keys
signature.asc
Description: OpenPGP digital signature
_______________________________________________ Soekris-tech mailing list [email protected] http://lists.soekris.com/mailman/listinfo/soekris-tech
