PCI Overload?

  • Thread starter Thread starter Cisephys
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Cisephys

Hi all, I'm in the process of switching my home network over to gigabit and
am running into a problem with my file server. The file server has a
Promise FastTrak S150 SX4 serial ATA RAID card with 3 drives in a RAID-5.
Now, in moving to gigabit, I purchased a Linksys 5 port gigabit switch and
a Linksys PCI gigabit NIC. Once I got it all installed though, despite
working fine for the most part, whenever I transferred files from the RAID
array over the gigabit connection to another machine, many of those files
would arrive at their destination corrupt. The file server's onboard
10/100 LAN does not have this problem, but forcing the Linksys card into
100 mode doesn't solve it. If, on my file server, I first copy the files
off of the array and onto the system drive (which is just a plain IDE drive
attached to the motherboard) and then transfer them over the network from
that drive, they all end up fine. Is it possible that between the RAID
array and the gigabit NIC going at the same time, there's just too much
going over the PCI bus at once? Any idea what I might be able to do about
this?

Thanks much,
Mike

P.S. I realize this is a bit off-topic for comp.networks and
comp.sys.ibm.pc.hardware.storage, but thought someone there might have
tried a similar setup to this and run into the same problem -- my
apologies!
 
Cisephys said:
Hi all, I'm in the process of switching my home network over to gigabit
and
am running into a problem with my file server. The file server has a
Promise FastTrak S150 SX4 serial ATA RAID card with 3 drives in a RAID-5.
Now, in moving to gigabit, I purchased a Linksys 5 port gigabit switch and
a Linksys PCI gigabit NIC. Once I got it all installed though, despite
working fine for the most part, whenever I transferred files from the RAID
array over the gigabit connection to another machine, many of those files
would arrive at their destination corrupt.
Click to expand...

Via chipset Mobo?
 
Cisephys wrote:
Is it possible that between the RAID
array and the gigabit NIC going at the same time, there's just too much
going over the PCI bus at once? Any idea what I might be able to do about
this?
Click to expand...


See if the same problem happens with a different Gigabit ethernet
card, if you can get one.
 
Cisephys said:
Hi all, I'm in the process of switching my home network over to gigabit and
am running into a problem with my file server. The file server has a
Promise FastTrak S150 SX4 serial ATA RAID card with 3 drives in a RAID-5.
Now, in moving to gigabit, I purchased a Linksys 5 port gigabit switch and
a Linksys PCI gigabit NIC. Once I got it all installed though, despite
working fine for the most part, whenever I transferred files from the RAID
array over the gigabit connection to another machine, many of those files
would arrive at their destination corrupt. The file server's onboard
10/100 LAN does not have this problem, but forcing the Linksys card into
100 mode doesn't solve it. If, on my file server, I first copy the files
off of the array and onto the system drive (which is just a plain IDE drive
attached to the motherboard) and then transfer them over the network from
that drive, they all end up fine. Is it possible that between the RAID
array and the gigabit NIC going at the same time, there's just too much
going over the PCI bus at once? Any idea what I might be able to do about
this?

Thanks much,
Mike

P.S. I realize this is a bit off-topic for comp.networks and
comp.sys.ibm.pc.hardware.storage, but thought someone there might have
tried a similar setup to this and run into the same problem -- my
apologies!
Click to expand...

The architecture of PCI allows it to work correctly, even when fully
saturated; i.e., don't blame PCI.

Individual PCI devices, and their device drivers, however may not work
correctly when the response times are large. Sad but true -- device
vendors are not required to test their devices & drivers on deeply
saturated PCIs.
 
Cisephys said:
Hi all, I'm in the process of switching my home network over to gigabit and
am running into a problem with my file server. The file server has a
Promise FastTrak S150 SX4 serial ATA RAID card with 3 drives in a RAID-5.
Now, in moving to gigabit, I purchased a Linksys 5 port gigabit switch and
a Linksys PCI gigabit NIC. Once I got it all installed though, despite
working fine for the most part, whenever I transferred files from the RAID
array over the gigabit connection to another machine, many of those files
would arrive at their destination corrupt. The file server's onboard
10/100 LAN does not have this problem, but forcing the Linksys card into
100 mode doesn't solve it. If, on my file server, I first copy the files
off of the array and onto the system drive (which is just a plain IDE drive
attached to the motherboard) and then transfer them over the network from
that drive, they all end up fine. Is it possible that between the RAID
array and the gigabit NIC going at the same time, there's just too much
going over the PCI bus at once? Any idea what I might be able to do about
this?

Thanks much,
Mike

P.S. I realize this is a bit off-topic for comp.networks and
comp.sys.ibm.pc.hardware.storage, but thought someone there might have
tried a similar setup to this and run into the same problem -- my
apologies!
Click to expand...

Another thought -- you might try fiddling with the PCI Latency Timer,
or whatever your MB's BIOS calls it. The default is either 32 or 64
ticks, and you might try setting it to something way shorter (8?).
This will certainly not cure bad device design; it is rather akin to
jiggling the handle on a toilet.

Also, you could try changing the MTU on your NIC to something really
small, like 128 bytes. The resulting datarate may be horrible, but it
might yield some insight.

You, as the system integrator, should certainly know that running SATA RAID
by itself will consume the DMA bandwidth of a standard (32b 33 MHz) PCI;
and that a GbE NIC will also consume a standard PCI. So, running them
both concurrently requires a faster flavor of PCI to extract full
throughput.

Good luck.
 
First, try increasing the chipset memory parameters.

Several products are know to have PCI problems: VIA chipsets, older Promise
cards, SB Live.
 
Jim said:
Is your system OC'd? If so, try while NOT OC'd.

Jim
Click to expand...

Hi Jim, thanks for the response -- nope, not OC'd at all. I've since found
that disabling the "Hardware Checksumming" feature in the NIC driver
settings seems to resolve the issue.

Mike
 
Via chipset Mobo?
Click to expand...

I appreciate the reply -- however, it's an NForce 2 motherboard. Seems as
though disabling the "Hardware Checksumming" feature on the NIC fixes the
issue, though I'm not yet sure if that might in itself raise more issues.

Mike
 
Cisephys wrote:
Is it possible that between the RAID


See if the same problem happens with a different Gigabit ethernet
card, if you can get one.
Click to expand...

I had actually tried this first with a D-Link card and had the same
problem. Turning off "Hardware Checksumming" in the driver settings on the
Linksys card seems to have fixed things, but I haven't been able to check
if the same tactic works on the D-Link card.

Mike
 
Cisephys said:
I appreciate the reply -- however, it's an NForce 2 motherboard. Seems as
though disabling the "Hardware Checksumming" feature on the NIC fixes the
issue, though I'm not yet sure if that might in itself raise more issues.
Click to expand...

I wouldn't worry about that.
 
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