> Muntz, Daniel <Dan.Muntz@xxxxxxxxxx> wrote: > > > AFS was designed to support local disk cache, so with callbacks > you can get a > > consistent system. > > It's less the callbacks and more the data version number that's important. Maybe for consistency, but for the performance benefits of local disk caching, I believe the callbacks are pretty important. I say that because I regularly use an NFS 3 filesystem on the IBM internal network that is painfully slow on Linux and fine on AIX with CacheFS. It was also fine when this data was in AFS instead, and if I copy all the files to a local disk filesystem. In this case, the files are _all in local page cache_, so I assume the waiting is for the constant stream of transactions the client uses to make sure the data in the cache is still current every time I open a file. AIX CacheFS doesn't sweat the consistency, so makes these queries only periodically. AFS had the callbacks, so rather than the client asking every time if the data had changed, the server just told it when it did. -- Bryan Henderson IBM Almaden Research Center San Jose CA Storage Systems -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
