|
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] RE: [Xen-users] Advice on redundant SAN/NAS storage for Xen
In my experience, effectively using DRBD is a major undertaking, and it can VERY easily cause you a lot of heartache. Approach with caution! Best Regards Nathan Eisenberg Sr. Systems Administrator Atlas Networks, LLC support@xxxxxxxxxxxxxxxx http://support.atlasnetworks.us/portal -----Original Message----- From: xen-users-bounces@xxxxxxxxxxxxxxxxxxx [mailto:xen-users-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Andrew Lyon Sent: Saturday, May 30, 2009 5:05 AM To: Fajar A. Nugraha; Chris 'Xenon' Hanson Cc: Xen User-List Subject: Re: [Xen-users] Advice on redundant SAN/NAS storage for Xen On Sat, May 30, 2009 at 6:30 AM, Fajar A. Nugraha <fajar@xxxxxxxxx> wrote: > On Sat, May 30, 2009 at 3:30 AM, Chris 'Xenon' Hanson > <xenon@xxxxxxxxxxxxxx> wrote: >> I'm planning to expand my Xen servers at my datacenter into a cluster with >> high >> availability and reliability. As part of this, I want to move all DomU >> storage to a common >> SAN or NAS infrastructure and make all the Dom0s basically identical. In >> this way, I can >> move DomU's around between Dom0s as needed for performance or reliability >> reasons. If a >> Dom0 server fails, I can just bring up its DomUs on different servers with >> no loss. > > Simple goal, not-so-simple implementation. > >> The best design I can think of is this: >> >> Two machines running Linux configured as SANs, using something like ATA over >> Ethernet >> (AoE) to link them to a pair of GigE switches that then link to every Dom) >> box. The pair >> of SAN boxes each export a block of raw storage that the Dom0 machine then >> RAIDs together >> as RAID1 and provides to Xen and the DomU as a block device. The Dom0 gets >> network-portable storage, with RAID reliability and redundancy. >> >> The other way might be to have the Dom0 and Xen pass through both block >> devices to the >> DomU and let the DomU RAID them together. I'm not sure if either is better. >> Maybe RAID on >> the DomU would allow the DomU to be migrated easier? > > RAID might be the weakest link here. Think what will happen if : > - one of the SAN box gets disconnected -> RAID will (hopefully) cope > with it well and use the live SAN > - some time later, the dead SAN is available again -> RAID won't > automatically re-add it > - the other SAN dies. > > These are big IFs, but you get the idea. > >> >> Is there a better and less messy way to provide redundant SAN-type storage >> to Xen DomUs? >> The main criteria are: >> >> Immune to failure of a single switch or SAN box. >> Allow DomUs to be moved seamlessly to other Dom0s without messy >> reconfiguration. > > Immune to a SAN box failure is hard. > The common way to do it in enterprise-level storage is to have high > availability in the SAN box. It does raid and have multiple > controllers in a cluster/HA setup so that it'd be "immune" enough to > disk or controller failure. I don't think there's a viable way to > achieve that with your planned setup. Feel free to correct me if I > wrong. > > -- > Fajar > > _______________________________________________ > Xen-users mailing list > Xen-users@xxxxxxxxxxxxxxxxxxx > http://lists.xensource.com/xen-users > Have a look at drdb, I've not used it myself but the idea of having two sets of disks (local or san) backing a single block device seems more robust than having two dom0's accessing the same storage. http://www.gridvm.org/drbd-lvm-gnbd-and-xen-for-free-and-reliable-san.html http://lists.xensource.com/archives/html/xen-users/2008-11/msg00828.html http://openqrm.com/storage-cluster.png Andy _______________________________________________ Xen-users mailing list Xen-users@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-users _______________________________________________ Xen-users mailing list Xen-users@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-users
|
 |
Lists.xenproject.org is hosted with RackSpace, monitoring our |
