This is me setting up a JBOD for use by one or more XEN hosts, using professional hardware. It’s not a hack, not throwing a shitload of drives into a PC with some “prosumer” SATA RAID cards that require you spend weeks fussing with drivers and firmware to get even a minimal write performance out of their underpowered hardware RAID.
A former roommate of mine once setup such a beast using a 12-port SATA card which ended up delivering a whopping 1 MBps of write speed in a RAID 5 configuration. I simply don’t have time to play around like that these days, so this is me trading capital for time.
The host machine is a Sun Fire X4200M2 server with an internal RAID10, running a RHEL 5.3 XEN installation. None of the services currently running on this box are critical, which means I can take them down for an hour at the end of the day without trouble, provided I can get them back up again. I also have the (Memorial Day) weekend to get the new JBOD up and running on this box.
After it’s up, however, I will be hosting important business-ey things on various virtual machines using this JBOD: e-mail, website(s), internal wiki, NAS, along with primary kerberos, LDAP, cobbler, puppet on the internal RAID; so it’s fairly important that this get up and working, and be stable once it’s going…
The JBOD itself is a Sun StorageTek J4200 array with a single IO module and a PCIe SAS RAID card, running 6x 1TB SATA disks in (eventually) a RAID6 array. I’d like to play around with interesting things like redundant SATA multipathing, but I’m pretty new to the whole storage admin area, so I’m not going to be playing around with those things on *this* setup…
James Cape 
Hi,
What’s the purpose of running a Xen installation ? Are you planning on serving files from a Xen guest ? If so, would you consider running an opensolaris distro for its ZFS capabilities! I am really interested in this exact setup, if you’re too, please let me know. Especially assigning raw disk access to the Xen guest.
Virtualization? Eventually I will be planning on serving files from the Xen guest, but I’m not going to assign it a raw disk per-se. The plan is to run the guests out of disk images inside LV stored on the JBOD (just as I’m doing on the internal array already).
I don’t know anywhere near enough about OpenSolaris or ZFS to trust my company’s core services to it.