I have a 6 drive (120 gig drives) RAID5 using a 3ware 7500-12. I have the latest firmware (7.5.1), latest driver etc, everything looks up to spec. I get great read speeds (60-80 megabyte/s), but I get very erratic write speeds (average 15 megabyte/s or so). Using "iostat -x 5" I see that writes are sometimes done at 25 meg/s to the raid5, some intervals at 5 meg/s, etc, with an average of approx 12-15 megabyte/s. Writes seem very jerky. Anyone seen this and solved it? I currently get better write speeds to a single IBM 7200rpm 75 gig drive (~25-30 meg/s) than to the 6 drive RAID5 volume (I use the 3ware card to create the volume, no software raid). 3ware support seems at a loss as to what causes this. I see it both with my SMP system and another UP system (both using Redhat 7.3 supplied kernels and the latest firmware/drivers for each card). I use ext3 in all all these cases. They suggested changing the bdflush values but I have already done that, and in my mind if it was a bdflush problem I would see the same problem to the single drive as well? -- Mikael Abrahamsson email: swmike@swm.pp.se - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
