Hi raider out there,
We have a fileserver with software RAID-5 here. It's a rackmountable
case
with 1 hardisk for the OS on one of the two onboard IDE controllers and
8
DNJA 20GB harddisk in CRU Dataport V cases connected to 4 Promise Ultra
66
cards (each has 2 buses).
So we installed a RAID5 over 5 disks with 3 spares for testing the
thing, and
it was pretty quick ( see bonnie results at the end of the mail). But it
had one
severe drawback:
We kept getting error messages under 'heavy' load ( RAID resync, e2fsck,
copying
a 2GB directory tree..) which looked as follows:
Jan 21 16:42:45 freshkills kernel: hdk: dma_intr: status=0x51 {
DriveReady SeekComplete Error }
Jan 21 16:42:45 freshkills kernel: hdk: dma_intr: error=0x84 {
DriveStatusError BadCRC }
Most of the times things just went fine, but sometimes the corresponding
harddisk
received a DMA reset:
Jan 19 21:16:39 freshkills kernel: hdk: DMA disabled
Jan 19 21:16:39 freshkills kernel: ide5: reset: success
Now most of the times when this happened the hole system just hang while
the
'red light' on the corresponding HD-case stayed red...
Sometimes we got lost interrupts afterwards, and once the raid
subsystems detected
the failure and started a rebuild with one of the spares.... but hang
after some very
short time....
Now via deja.com, we narrowed the cause of the problem down to
cabling!!!!!!
Though we use the special cables they have to be too long, as the
standard rack-mountable
case is too big with PCI-slots in the back and HD's in the front.
And the fact that the HD-cases use som additional cable inside and add
another connector
is not very helpful neither!!!!
So for the moment we use normal cables again, which makes the disk fall
back to UDMA33 and
the errors seem to be gone!!!!!!! :-)
But in the end we would prefer the UDMA66 back, especially because of
the block-read performance loss
of 1 third....
So what we need is a smaller rackmountable case.
And we wondered whether there are some raiders out there which
successfully use
UDMA66 RAID in a rackmountable case and with HD-cases and what
rackmountable
case they are using......
I thought maybe somebody would be interested in a little 'linup' of
UDMA66 versus UDMA33...:-)
Both are for a RAID-5 system with 5 disks, done in single user mode.
RAM is 128MB and its a single PIII 500Mhz if I am not mistaken....
Interestingly writes do not seem to suffer but block-writes pretty
heavily...
And that with 1HD/ UDMA66 bus!!!!!!
Wasn't there once a mail from somebody saying that todays HD's wont fill
even
the UDMA33 capacity....
-------Sequential Output-------- ---Sequential
Input-- --Random--
-Per Char- --Block--- -Rewrite-- -Per Char-
--Block--- --Seeks---
MB K/s %CPU K/s %CPU K/s %Cpu K/s %CPU K/s
%CPU /s %CPU
:::::::::::::first run UDMA66
2047 7184 90.2 28856 23.2 17191 32.5 8301 97.5
60630 43.0 201.1 3.7
::::::::::::::second run UDMA66
2047 7183 90.2 29521 24.1 17086 31.7 8305 97.5
60009 43.3 201.6 2.8
::::::::::::::UDMA33
2047 7153 90.0 29793 24.1 14619 26.6 8250 96.9
40113 27.9 161.3 2.8
anyway,
would be nice if people could respond with their rackmountable cases
information...
and:
did anybody get the above mentioned errors and crashes even with short
enough
cables and no HD-cases?????
have fun raiding
remo
