Dave Gilbert wrote:
>
> On Sat, 1 Apr 2000, W Bauske wrote:
>
> > Even at 9MB/sec, that's sufficient for what I want.
> > The files will be passed across fast Enet so anything
> > close to or faster than 100Bt is fine for what I want.
>
> Good - I'd really like to know if anyone gets any better.
Some progress. I put together 2.3.99pre4.
Compilation is troublesome but if you don't select
the new net filtering code, it builds.
Odd things when it booted:
1. It loses the floppy drive. 2.2.14 finds it fine.
2. It loses the IDE drive on the secondary channel of
the Promise card. It does report the channel exists.
3. I tried a hdparm -Tt /dev/hda and it says the
SHM file system is not mounted?? I did select
SYSV IPC which is where I believe SHM lives.
One good thing. Promise UATA66 performance is good,
on the order of 20MB/sec for my Maxtor 40GB drive
it did find. It is unstable however. Locked as I
attempted to copy around 30GB of data from a disk
on the Cypress IDE to the Promise. I'm not sure
which side locked up though. The Promise has been
stable so far under 2.2.14, excluding the fact it
doesn't want to write past 8GB which I don't think
is the Promise's problem but then again, the Promise
reports the drive as an 8GB device so it might be
the Promise's fault.
I think I'm going to try a 2.2.15pre/ac level and
see how that does. At least it seems the Promise
is capable of a reasonable speed. Now if it can
only run stable.
> Hmm - mean system! At work we have an external EIDE RAID box which chucks
> SCSI out the back; I don't know the manufacturer, but it takes 6 IDE
> drives (we use the IBM 34 GXPs) - standard drives as far as I'm aware. I
> think it was about #4000 UKP when we bought them about 6 months ago.
> Might be worth looking to see if any of your suppliers have anything
> similar.
>
I've seen them but the box itself raises the cost
almost to the same price as SCSI so it didn't seem
like a good deal. My main interest is $/MB. I regularly
fiddle around with several 100GB of data and at times
more than one set of data so it consumes lots of disk
space.
> Another thing to look at is CPU usage; I don't know how much this would be
> different on a nice juicy UP2K, but on my LX:
>
> time dd if=/dev/hdc of=/dev/null bs=1024k count=100
>
> gives:
>
> 0.00user 1.54system 0:08.71elapsed 17%CPU (0avgtext+0avgdata
> 0maxresident)k
> 0inputs+0outputs (97major+145minor)pagefaults 0swaps
I suspect an EV67 can cut the cpu utilization significantly.
Even SCSI consumes a substantial amount of cpu as the disk speed
increases. Still, though, it's limited by the 100BT.
>
> Another thing to remember is that the data transfer rate can vary
> significantly over the surface of the disc.
>
Yup, on the order of 50%/100% or so depending on how
you look at it. My Maxtors go from about 13MB/sec to
24MB/sec.
Wes
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