Let me elaborate slightly on the reason I ask these questions. I am performing some simple benchmarking, and during this a file is created by sequentially writing 64k blocks until the 100Gb file is created. I am seeing, and this is the exact same as VxFS, large pauses while the system reclaims the memory that it has consumed.
I assume that since ZFS (back to the write cache question) is copy-on-write and is not write caching anything (correct me if I am wrong), it is instead using memory for my read-cache. Also, since I have 32Gb of memory the reclaim periods are quite long while it frees this memory - basically rendering my volume unusable until that memory is reclaimed. With VxFS I was able to tune the file system with write_throttle, and this allowed me to find a balance basically whereby the system writes crazy fast, and then reclaims memory, and repeats that cycle. I guess I could modify c_max in the kernel, to provide the same type of result, but this is not a supported tuning practice - and thus I do not want to do that. I am simply trying to determine where ZFS is different, the same, and where how I can modify its default behaviours (or if I ever will). Also, FYI, I'm testing on Solaris 10 11/06 (All testing must be performed in production versions of Solaris) but if there are changes in Nevada that will show me different results, I would be interested in those as an aside. This message posted from opensolaris.org _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
