Hi, You say you stress tested this setup. Can you tell me your experiences with hotplugging in combination with SATA disks (which you are using). I seem to keep getting kernel panics when hotplugging SATA disks with the same controller, kernel and patches you mention. I mentioned this (with several others in this mailinglist) some time ago but no reaction since. Kind regards, Caspar Smit > I have 8 Western Digital WD15EADS 1.5T green drives in a software > raid6 6+2 config using 1024K chunk size. > They are connected to a SuperMicro SASLP-MV8 card sitting in the 16x > PCI-E slot of an old but stable Asus K8N4E-Deluxe board. > > Every single drive appears to read at >90Mbyte/sec: > hdparm -t /dev/sdb > Timing buffered disk reads: 282 MB in 3.02 seconds = 93.49 MB/sec > > But when I try to hdparm -t /dev/md2, I max out at around 180Mbyte/sec > and the read seems to be nicely distributed across all drives > according to iostat -k : > > avg-cpu: %user %nice %system %iowait %steal %idle > 5.00 0.00 95.00 0.00 0.00 0.00 > > Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn > sda 0.00 0.00 0.00 0 0 > sdb 115.00 23552.00 0.00 23552 0 > sdc 110.00 22528.00 0.00 22528 0 > sdd 115.00 23552.00 0.00 23552 0 > sde 115.00 23552.00 0.00 23552 0 > sdf 113.00 23040.00 0.00 23040 0 > sdg 112.00 23040.00 0.00 23040 0 > sdh 119.00 24324.00 0.00 24324 0 > sdi 121.00 24576.00 0.00 24576 0 > md2 47783.00 191132.00 0.00 191132 0 > > sda is my boot drive connected to the onboard nforce, not part of the > raidset > > When loading the mvsas module, it seems the bandwith is limited: > mvsas 0000:01:00.0: mvsas: PCI-E x4, Bandwidth Usage: 2.5 Gbps > > which seems strange as it should be able to do 250Mbyte/sec per lane, > so 4 lanes should amount to 1 Gbyte / sec even for the oldest PCI-E > v1.x standard. > > My system is Fedora 12 x86_64 using a custom 2.6.32.3 kernel with the > following patches from Andy Yan: > > [PATCH 6/7]MVSAS: Enhanced hot plug handling > [PATCH 5/7]MVSAS:Optimization for DMA buffer > [PATCH 4/7]MVSAS:Make code more flexibe for different chip model. > [PATCH 3/7]MVSAS: bug fix with big endian > [PATCH 2/7]MVSAS:add supporting MSI feature > [PATCH 1/7]MVSAS: Update chip initialization > > I did not use [PATCH 7/7] > > I can report these patches solved all of my raid6 stability issues > (drives kicking out of the raid, /proc/mdstat not reporting faults, > xfs corruption) and have been running stable for the past 3 weeks with > all sorts of stress testing. > > Am I missing something with regards to tuning to get the full > bandwidth out of this marvell controller ? > -- > To unsubscribe from this list: send the line "unsubscribe linux-scsi" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
