Jeff Darcy wrote: > On 12/27/12 6:47 PM, Miles Fidelman wrote: >> John Mark Walker wrote: >>> In general, I don't recommend any distributed filesystems for VM >>> images, but I can also see that this is the wave of the future. >> Ok. I can see that. >> >> Let's say that I take a slightly looser approach to high-availability: >> - keep the static parts of my installs on local disk >> - share and replicate dynamic data using gluster > That, in a nutshell, is the approach that I (and others) often advocate. Block > storage should be used sparingly, e.g. for booting and for data served to > others at a higher level. I'd say that's true in general, but it's especially > true for any kind of network block storage. When network latencies are > involved, going "up the stack" where operations are expressed at a high > semantic level will almost always work out better than blocks and locks. What's the alternative, though? Ok, for application files (say a word processing document) that works, but what about spools, databases, and such? Seems like blocks are the common denominator. >> - data is triply replicated (allow for 2-node failures) > Unfortunately, three-way replication is still a bit of a work in progress. > Some (such as Joe Julian) use it successfully, but they also use it very > carefully. I've had to make a few fixes in this area myself recently, and I > expect to make a few more before I'd say that it's really up to snuff for > general use. That's a bit disappointing. For high-availability applications (like mine), 3-way replication would seem to be the major advantage of a cluster file system over DRBD. Thanks, Miles Fidelman -- In theory, there is no difference between theory and practice. In practice, there is. .... Yogi Berra
