Web Hosting Talk : Web Hosting Main Forums : Hosting Security and Technology : UDMA Probs

[NWSTech]

hi,
i have just got a new server but i have one problem, UDMA mode will not turn on on the hard drives and is therefore killing the disk performance altogether, its RH9 with cpanel, anyone got any ideas what the problem is here

and before you ask the output of hdparm -d1 /dev/hda is
/dev/hda:
setting using_dma to 1 (on)
HDIO_SET_DMA failed: Operation not permitted
using_dma = 0 (off)

[Lightwave]

plz run hdparm -i /dev/hda

[NWSTech]

hope you lot understand this better than i do -

/dev/hda:

Model=WDC WD800BB-22FJA0, FwRev=13.03G13, SerialNo=WD-WCAJ91505079
Config={ HardSect NotMFM HdSw>15uSec SpinMotCtl Fixed DTR>5Mbs FmtGapReq }
RawCHS=16383/16/63, TrkSize=0, SectSize=0, ECCbytes=58
BuffType=unknown, BuffSize=2048kB, MaxMultSect=16, MultSect=16
CurCHS=16383/16/63, CurSects=16514064, LBA=yes, LBAsects=156301488
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
AdvancedPM=no WriteCache=enabled
Drive conforms to: device does not report version:

* signifies the current active mode

[Lightwave]

The key there is that it states you're already using UDMA2 mode.

For systems which have all of the pre-requisites for UDMA mode 3 and 4 and a hard drive capable of UDMA modes 3 and 4 a special 80 wire, 40-pin interface cable is required. The 80 wire cable reduces crosstalk and improves signal integrity by providing 40 additional ground lines between the 40-pin IDE signal and ground lines. Due to the higher transfer rate and shorter cycle times of the data transfers this cable is required to achieve UDMA mode 3 and 4 performance.

So to go up any higher... make sure it's supported by your motherboard, enabled in your BIOS, and that you're using the proper connector.

It SHOULD set itself automagicaly to the highest aviailable.

If you're daring you can use

hdparm

-X68 -> ATA-66 (UDMA 4)
-X69 -> ATA-100 (UDMA 5)

ie
hdparm -X68 /dev/hda

but this could completely cause all data to be destroyed/lost.

[NWSTech]

yes but heres something else that doesnt add up - the theoretical transfer rate of udma 2 is 33mb/s

but i am only getting.....

hdparm -tT /dev/hda

/dev/hda:
Timing buffer-cache reads: 3040 MB in 2.00 seconds = 1520.00 MB/sec
Timing buffered disk reads: 12 MB in 3.16 seconds = 3.80 MB/sec

and this is the hdparm -i list from my other server

/dev/hda:

Model=HDS728080PLAT20, FwRev=PF2OA21B, SerialNo=PFD212S2TNTV6E
Config={ HardSect NotMFM HdSw>15uSec Fixed DTR>10Mbs }
RawCHS=16383/16/63, TrkSize=0, SectSize=0, ECCbytes=51
BuffType=DualPortCache, BuffSize=1719kB, MaxMultSect=16, MultSect=16
CurCHS=16383/16/63, CurSects=16514064, LBA=yes, LBAsects=160836480
IORDY=on/off, tPIO={min:240,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=yes: disabled (255) WriteCache=enabled
Drive conforms to: Reserved:

* signifies the current active mode


and this is the read performance -

hdparm -tT /dev/hda

/dev/hda:
Timing buffer-cache reads: 1052 MB in 2.00 seconds = 526.00 MB/sec
Timing buffered disk reads: 172 MB in 3.03 seconds = 56.77 MB/sec


somewhat different their

[NWSTech]

and changing the transfer rate makes no difference -
hdparm -X68 /dev/hda

/dev/hda:
setting xfermode to 68 (UltraDMA mode4)
root@server4 [~]# hdparm -tT /dev/hda

/dev/hda:
Timing buffer-cache reads: 3048 MB in 2.00 seconds = 1524.00 MB/sec
Timing buffered disk reads: 12 MB in 3.27 seconds = 3.67 MB/sec

[NWSTech]

any idea whats happening here and how to fix it - need to know ASAP