You might be able to go a simpler route, try building a GFBD between them and sharing the storage that way. I personally have never tried it, but that might give you the HA you're looking for while staying withing the CentOS/Upstream packaging. One added benefit is the ability to scale vertically and horizontally with a setup like that with failover and quorum. Heck, toss in a little heartbeat scripting and you could call it an auto-healing storage cloud. Good luck! On Fri, May 20, 2011 at 5:28 PM, John R Pierce <pierce at hogranch.com> wrote: > I'm interested in the idea of sharing a bunch of SAS JBOD devices > between two CentOS servers in an active-standby HA cluster sort of > arrangement, and found something about using scsi3 persistent > reservations as a fencing method. I'm not finding a lot of specifics > about how this works, or how you configure two initiator systems on a > SAS chain. I don't have any suitable hardware for running any tests or > evaluations yet. > > general idea: 2 centos servers each with 8 port external SAS cards (2 > x4), cascaded through a SAS box-o-disks with a whole bunch of SAS dual > ported drives, to implement high availability large nearline > storage. all storage configured as JBOD, using linux md raid or > lvm mirroring. drives should only be accessible by the currently active > server, with heartbeat managing the fencing. > > here's a hardware block diagram > http://freescruz.com/shared-sas.jpg > > > This is about the only details I've found on scsi persistant > reservations and linux HA > http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/5/html/Configuration_Example_-_Fence_Devices/SCSI_Configuration.html > > One question I have is: how well will this scale with several strings of > 100 SAS drives on the same HA pair of servers? > > Can SAS storage instead be fenced at the SES/expander level rather than > having to use reservations with each separate drive? > > -- > john r pierce N 37, W 123 > santa cruz ca mid-left coast > > _______________________________________________ > CentOS mailing list > CentOS at centos.org > http://lists.centos.org/mailman/listinfo/centos > -- Steven Crothers steven.crothers at gmail.com
