Hi all, I've noticed something strange in the throughput in my zpool between different snv builds, and I'm not sure if it's an inherent difference in the build or a kernel parameter that is different in the builds. I've setup two similiar machines and this happens with both of them. Each system has 16 2TB Samsung HD203WI drives (total) directly connected to two LSI 3081E-R 1068e cards with IT firmware in one raidz3 vdev.
In both computers, after a fresh installation of snv 134, the throughput is a maximum of about 300 MB/s during scrub or something like "dd if=/dev/zero bs=1024k of=bigfile". If I bfu to snv 138, I then get throughput of about 700 MB/s with both scrub or a single thread dd. I assumed at first this was some sort of bug or regression in 134 that made it slow. However, I've now tested also from the fresh 134 installation, compiling the OS/Net build 143 from the mercurial repository and booting into it, after which the dd throughput is still only about 300 MB/s just like snv 134. The scrub throughput in 143 is even slower, rarely surpassing 150 MB/s. I wonder if the scrubbing being extra slow here is related to the additional statistics displayed during the scrub that didn't used to be shown. Is there some kind of debug option that might be enabled in the 134 build and persist if I compile snv 143 which would be off if I installed a 138 through bfu? If not, it makes me think that the bfu to 138 is changing the configuration somewhere to make it faster rather than fixing a bug or being a debug flag on or off. Does anyone have any idea what might be happening? One thing I haven't tried is bfu'ing to 138, and from this faster working snv 138 installing the snv 143 build, which may possibly create a 143 that performs faster if it's simply a configuration parameter. I'm not sure offhand if installing source-compiled ON builds from a bfu'd rpool is supported, although I suppose it's simple enough to try. Thanks, Chad Cantwell _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
