Hi, If your software doesn't support TRIM then SSD write performance (and read, to a lesser extent) will start to suck once the disk has had a certain amount of use. Don't know if this applies in your case.
On 11 Mar 2014, at 10:32, Karsten Kruse <[email protected]> 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: > > > [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>_______________________________________________ > Soekris-tech mailing list > [email protected] > http://lists.soekris.com/mailman/listinfo/soekris-tech -- Bob Bishop [email protected] _______________________________________________ Soekris-tech mailing list [email protected] http://lists.soekris.com/mailman/listinfo/soekris-tech
