Politics and Technology.

Friday, June 29, 2007

Stratus FT 4300 and RHEL

We've started to evaluate Stratus' FT4300 using Red Hat Enterprise Linux.

What we've learned so far is impressive: the server operates as robustly as it would with VOS. After installation, we've unplugged modules while running a video from the RHEL server. It never missed a beat.

It should be noted, however, that I/O redundancy is handled by RHEL as the hardware presents all the I/O channels, and not some kind of metadevice that represents a redundant pair of paths.

We did entitle the RHEL server to our Satellite server and noticed one problem right off the bat: the RHEL installed by Stratus required connectivity to their yum server for updates. We commented this line out from /etc/sysconfig/rhn/sources:

yum Stratus_Technologies_ft_Linux_4.0 http://pman3.com/ftLinux/4.0/

And ran up2date. It complains about initscripts, right away:

Testing package set / solving RPM inter-dependencies...
There was a package dependency problem. The message was:

To solve all dependencies for the RPMs you have selected, The following
packages you have marked to exclude would have to be added to the set:

Package Name Reason For Skipping
initscripts-7.93.29.EL-1 Config modified

Now, one would be tempted to run "up2date -f" and force the issue, but I knew right away that Stratus had to have its hooks in somewhere. You see, even though the I/O redundancy is handled by RHEL, the hardware remains aware of when there is lack of redundancy. For instance, after replaceing the power on one of the modules after testing its resiliencey, RHEL's MD had to remirror the root drive. During this time, the hardware flashed its led's in that characteristic way that VOS systems due to signal that systems are not currently in a redundant and fail-safe mode. Once mdadm showed the mirroring to be complete, the lights stopped flashing.

A quick run of rpm's verify showed exactly what configuration files were altered:

[root@sbkrhelstratp01 rhn]# rpm -Vc initscripts
S.5....T. c /etc/inittab
S.5....T. c /etc/rc.d/rc.sysinit
[root@sbkrhelstratp01 rhn]#

A careful scan of the rc.sysinit file drew my attention to several operations that were commented on by Stratus. These seemed to involve RAID. I fully expected to find something in inittab requiring respawns, and sure enough, there they were:


My options at this point include saving copies of these and force the up2date, or perhaps reach out to the yum server at Stratus and see if it keeps an updated rpm of initscripts.

Ideally, I'd like to create a custom software channel on my satellite server based upon the yum server at Stratus.

Right now, I'm stalled.

No comments: