On Thu, Apr 19, 2001 at 03:41:38PM -0700, Eugene Chu wrote:
> Does anyone know if there is a Fiberchannel card that works under
> Alpha linux? I recall some discussions a while back about using an
> Emulex LPFC8000, but the closest thing I could find on their site is
> a driver for Pentium linux.
We have been trying to get some stable fiber channel support to work
under Alpha (XP1000, linux 2.2.XX, currently 19) at our site here for
some time. I have not seen any support for the Emulex driver for Alpha
Linux. When a colleague contacted Emulex directly they indicated they
had no plans to support Alpha. This was 3 months ago.
We have Qlogic 2200 cards here. There are 3 driver options for you on
1) Qlogic (www.qlogic.com)
2) UNH (not sure, but it is the driver that is in the kernel source)
3) Feral (www.feral.com)
I have spent most of my time with 1 and 3. I have not tried the
driver from UNH. There have been some problems with data corruption
when the machine is under heavy load for (1) and (2). I have seen
it happen for (1), and GFS reported the problem for (2). For qlogic's
driver, that was relevant to version 2.XX. It seems that version
4.XX-beta no longer has the driver corruption. Also, qlogic's 4.XX-beta
actually acknowledges the Alpha platform and will compile cleanly which
the older drivers would not do.
To test for corruption, I would execute numerous dd commands and
simultaneous kernel compiles on different file systems on one node
for ext2 and on several nodes for GFS (Global File System, www.sistina.com)
I think that I isolated the problem to only reads off of the FC device as the
kernel compiles would always fail in different places after untarring the
directory. When there was no load I could compile the kernel successfully.
The 3rd driver shows promise. It is from Feral Software,
Matt Jacob is the author. I was having much better luck with that driver
before I got the latest qlogic driver. There was no data corruption with
this driver but some of the GFS authors reported some SMP
issues. The latest driver is having some problems as Matt is trying
to redo some code relating to card initialization (I don't remember
The last 2 weeks I have been mounting an ext2 filesystem from an
XP1000 with 2GB of ram on linux 2.2.19 and the Qlogic qla2x00-4.24Beta
driver. The machine has hung once in that time. I am also exporting
the filesystem with NFS to 30 nodes over myrinet-ip.
Performance is a big issue as well. I know that I should be able
to max out the FC link from the XP1000 to our SAN. There is other
traffic on the SAN but I have never gotten better than 55 MB/s for
writes and 35 MB/s reads for an ext2 file system. There was other
activity on the system Our SAN should be able to max out the FC link
(100Mb/s theoretical). Performance on an SGI is 90 MB/s for writes and
50 MB/s for reads (xfs vs. ext2, but I don't think the performance should
be that different, but I could be wrong). We can max out the
SAN with multiple clients accessing different filesystems for ext2 or the
same filesystem under GFS. I tried an older version of the Feral driver
and single node performance results weren't any better. Writes were worse
slightly and reads were about the same.
I want to try out linux 2.4.XX and see if the direct-IO patches
can help with the performance. Kernel 2.4.3 has some build problems for
alpha. I am aware of the patches from Andrea that are supposed to fix them
but I have not had success and I have not had time to figure out what
the problem really is.
> One follow-on question has to do with SAN type environments. If I
> created an ext2 file system on a disk partition using Alpha linux,
> would a Pentium linux system be able to mount and use it? In other
> words, are the ext2 file systems for both systems the same format?
I never have tried this.
For more information, you can look around the GFS site (www.sistina.com)
as they have a lot of experience with FC channel drivers. Mostly
x86 but some alpha. In the Changelogs of each release
the GFS authors provide some information about different FC drivers and
their experiences with them.
-- Craig Tierney (firstname.lastname@example.org) phone: 303-497-3112
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