My newly bought hdd-s seem to have lower than expected rw-speed

MasterOfTheWind · 06-20-2008, 03:30 PM

Hi!

I have recently bought 2 hdds, they run absolutely fine, but after doing some benchmarks I think that may be some configuration is wrong, because read speed seems sort of substandard:

Western Digital Raptor 74GB SATA 16MB 10000RPM
hdparm -t /dev/sda => 85 mb/s
hdparm -T /dev/sda => 1700 mb/s

Western Digital Caviar GP 500GB SATA2, 16MB 7200RPM
hdparm -t /dev/sdb => 75 mb/s
hdparm -T /dev/sdb => 1700 mb/s

I at least expected the Raptor (with 10k rpm) to be quicker than this. Does anyone know what I may be doing wrong?

### ATTACHMENT: output of "hdparm -i" ###

Code:

 Config={ HardSect NotMFM HdSw>15uSec SpinMotCtl Fixed DTR>5Mbs FmtGapReq }
 RawCHS=16383/16/63, TrkSize=57600, SectSize=600, ECCbytes=48
 BuffType=DualPortCache, BuffSize=16384kB, MaxMultSect=16, MultSect=?16?
 CurCHS=16383/16/63, CurSects=16514064, LBA=yes, LBAsects=145226112
 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: ATA/ATAPI-7 published, ANSI INCITS 397-2005:  ATA/ATAPI-1,2,3,4,5,6,7

 * signifies the current active mode

Code:

 Config={ HardSect NotMFM HdSw>15uSec SpinMotCtl Fixed DTR>5Mbs FmtGapReq }
 RawCHS=16383/16/63, TrkSize=0, SectSize=0, ECCbytes=50
 BuffType=unknown, BuffSize=16384kB, MaxMultSect=16, MultSect=?16?
 CurCHS=16383/16/63, CurSects=16514064, LBA=yes, LBAsects=976773168
 IORDY=on/off, tPIO={min:120,w/IORDY:120}, tDMA={min:120,rec:120}
 PIO modes:  pio0 pio3 pio4 
 DMA modes:  mdma0 mdma1 mdma2 
 UDMA modes: udma0 udma1 udma2 udma3 udma4 udma5 *udma6 
 AdvancedPM=no WriteCache=enabled
 Drive conforms to: Unspecified:  ATA/ATAPI-1,2,3,4,5,6,7

 * signifies the current active mode

tredegar · 06-20-2008, 05:15 PM

It is working as best as it can (udma6).

What is wrong with 85MB/s?

If it "works fine" then what is your problem?

Why have you posted your code in such a tiny font? It's impossible to read. The LQ defaults are fine, and preferable.

amani · 06-20-2008, 05:21 PM

Looks OK.

Are the Sata settings ok: jumpers, AHCI ?

MasterOfTheWind · 06-21-2008, 01:46 AM

Thank you both for your replies

Quote:

Originally Posted by tredegar

What is wrong with 85MB/s?

I sort of expected more. Since it is supposed to be a 10k rpm harddisk. HDDs in my 5yo comp have about the same speed - and they were the cheapest I could get at the time.

Quote:

Originally Posted by tredegar

If it "works fine" then what is your problem?

They work, sure. But I have spent quite a lot money on that Raptor, and I would rather like that it runs to the max of its capacity. Otherwise I could just have bought another Caviar with 6 times more storage space and almost the same read speed.

Quote:

Originally Posted by tredegar

Why have you posted your code in such a tiny font? It's impossible to read. The LQ defaults are fine, and preferable.

Fixed. But you did manage to read the "udma6*", right? So I guess it's not *that* bad. And besides, maybe your browser font size settings need adjustmest - I for one am able read those font=1 lines fine.

Quote:

Originally Posted by amani

Are the Sata settings ok: jumpers, AHCI ?

Well, I tried setting jumpers to OPT1 mode, which is supposed to allow 150MB/s transfer rates. But that didn't do much at all. While AHCI is another story. I had to disable it to achieve at least decent speeds. With AHCI on, I would get something like 25mb/s (both when trying the hdparm test and a manual "dd if=/dev/sda of=/dev/null"), but the result would fluctuate much: one second it could be 50mb/s and if you tested it again right afterwards it could be down at 15mb/s.

strick1226 · 06-23-2008, 11:00 AM

The increased spindle speed of the Raptor isn't so much about delivering greater transfer rates as it is in focusing on markedly lower seek times.

If you want extreme transfer rates, put two drives in a striped (RAID 0) config... of course, then there's no redundancy, so there is a tradeoff.

85 MB/s is nothing to sneeze at, performance-wise. Sure, it's not a full 133 MB/s as the UDMA6 spec provides, but you'll be hard pressed to find any drive out there that can run that speed in a standalone configuration (that doesn't require NASA's budget).

Sorry the Raptor isn't exactly what you expected. For what it's worth, I think they're great drives, and use them myself. But if you want the most performance, you'll need to set up some kind of RAID config with at least two of the puppies.

MasterOfTheWind · 06-24-2008, 09:32 AM

Thanks for a great explanation, strick1226

I *do* notice the shorter seek times since I have my root fs on the Raptor, from a purely subjective standpoint - I haven't done any benchmarks