[aperi-dev] Discovering and probing Linux devices

["Robert Wipfel" <rawipfel@xxxxxxxxxx>]

Hi,

I checked with Novell's Linux kernel folks who offered some advice on the 
most portable way to probe devices on Linux. Below is how they answered;
we thought best to share here in transparent OSS fashion ;)

/proc/partitions        (works on almost anything)
/sys/block/*            (kernel 2.6.x)

/sbin/*_id              (recent udev & kernel 2.6.x)

hwinfo -- storage        (suse only)
hwinfo -- disk           (suse only)

Aperi's native Linux agent code is using /proc/ide and /proc/scsi to find things;
and we've been looking into the changes required to update this for recent
kernels in the enterprise distros. This will also allow for discovery of attached
devices, from inside a Xen virtual machine (because Xen's virtual block devices
can't be found via e.g. /proc/ide even though the guest OS is unaware its IDE
boot/root disk is hosted by Xen). Fyi: the Aperi agent does run inside a Xen VM
but won't register because it can't find any disks - though I can see the VMs in
the Aperi GUI.

We've also run into problems on newer servers with SATA boot disks that
show up in /proc/scsi; the native Linux ProbeSCSI() code called when the Agent
starts up, is crashing the JVM and the Agent fails.

So we're trying to figure out how to build the Aperi code on Linux for Linux...

Thanks,
Robert

P.S. Re: Khan's comment that most developers don't have an enterprise SAN
to play with; that's true, but a Lenovo T60p with Xen kernel and iSCSI is a great
development platform - I can run Aperi, multiple virtual machines, and shared
block storage, all on one laptop :-)