On Mon, Aug 30 at 15:05, Ray Van Dolson wrote:
I want to "fix" (as much as is possible) a misalignment issue with an X-25E that I am using for both OS and as an slog device.This is on x86 hardware running Solaris 10U8. Partition table looks as follows: Part Tag Flag Cylinders Size Blocks 0 root wm 1 - 1306 10.00GB (1306/0/0) 20980890 1 unassigned wu 0 0 (0/0/0) 0 2 backup wm 0 - 3886 29.78GB (3887/0/0) 62444655 3 unassigned wu 1307 - 3886 19.76GB (2580/0/0) 41447700 4 unassigned wu 0 0 (0/0/0) 0 5 unassigned wu 0 0 (0/0/0) 0 6 unassigned wu 0 0 (0/0/0) 0 7 unassigned wu 0 0 (0/0/0) 0 8 boot wu 0 - 0 7.84MB (1/0/0) 16065 9 unassigned wu 0 0 (0/0/0) 0 And here is fdisk: Total disk size is 3890 cylinders Cylinder size is 16065 (512 byte) blocks Cylinders Partition Status Type Start End Length % ========= ====== ============ ===== === ====== === 1 Active Solaris 1 3889 3889 100 Slice 0 is where the OS lives and slice 3 is our slog. As you can see from the fdisk partition table (and from the slice view), the OS partition starts on cylinder 1 -- which is not 4k aligned. I don't think there is much I can do to fix this without reinstalling. However, I'm most concerned about the slog slice and would like to recreate its partition such that it begins on cylinder 1312. So a few questions: - Would making s3 be 4k block aligned help even though s0 is not? - Do I need to worry about 4k block aligning the *end* of the slice? eg instead of ending s3 on cylinder 3886, end it on 3880 instead? Thanks, Ray
Do you specifically have benchmark data indicating unaligned or aligned+offset access on the X25-E is significantly worse than aligned access? I'd thought the "tier1" SSDs didn't have problems with these workloads. --eric -- Eric D. Mudama edmud...@mail.bounceswoosh.org _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
