SCSI performance using the raw device under RH WS 3 seems to be degraded from what it was under RH 7.2. It seems to peek around about 152 MB/s vs. 290 MB/s under RH 7.2, this is with the same hardware. They have tried both the on board LSI MPT Fusion controller and an Adaptec 39160 controller with similar poor results. They think it might be the raw device, but are not sure and have probably eliminated the SCSI drivers themselves. Customer also tried compiling Linus-series 2.4.21 and 2.4.22 kernels and confirmed that performance is fine against that baseline. /etc/sysconfig/rawdevices looks like: /dev/raw/raw1 /dev/md0 /etc/raidtab looks like: raiddev /dev/md0 raid-level 0 nr-raid-disks 4 chunk-size 64k persistent-superblock 1 nr-spare-disks 0 device /dev/sdb raid-disk 0 device /dev/sdc raid-disk 1 device /dev/sdd raid-disk 2 device /dev/sde raid-disk 3 cat /proc/scsi/scsi looks like: Attached devices: Host: scsi0 Channel: 00 Id: 00 Lun: 00 Vendor: SEAGATE Model: ST318453LW Rev: HPS1 Type: Direct-Access ANSI SCSI revision: 03 Host: scsi0 Channel: 00 Id: 01 Lun: 00 Vendor: SEAGATE Model: ST336753LW Rev: 0003 Type: Direct-Access ANSI SCSI revision: 03 Host: scsi0 Channel: 00 Id: 02 Lun: 00 Vendor: SEAGATE Model: ST336753LW Rev: 0003 Type: Direct-Access ANSI SCSI revision: 03 Host: scsi1 Channel: 00 Id: 01 Lun: 00 Vendor: SEAGATE Model: ST336753LW Rev: 0003 Type: Direct-Access ANSI SCSI revision: 03 Host: scsi1 Channel: 00 Id: 02 Lun: 00 Vendor: SEAGATE Model: ST336753LW Rev: 0003 Type: Direct-Access ANSI SCSI revision: 03 HOW THIS WAS TESTED - The test is available at: http://tiobench.sourceforge.net/ You have to modify the makefile slightly to allow for large mem access when building. #DEFINES=-DLARGEFILES A common test line is: ./tiotest -d /mnt/rawdevice -t 7 -f 4096 -b 1048576 This can be tuned by several parameters which are available via the --help command to optimize results. The main idea here is to saturate the pipe of the raw device between sends, which is the way to guage true throughput. Obviously the larger your pipe the larger the packets you want to send per transmission. FOLLOWING is the result for 2.4.21 kernel ./tiotest -d /movie -t 1 -b 1048575 -f 4096 Tiotest results for 1 concurrent io threads: ,----------------------------------------------------------------------. | Item | Time | Rate | Usr CPU | Sys CPU | +-----------------------+----------+--------------+----------+---------+ | Write 4096 MBs | 21.0 s | 195.103 MB/s | 0.1 % | 49.3 % | | Random Write 1000 MBs | 15.3 s | 65.285 MB/s | 0.0 % | 15.9 % | | Read 4096 MBs | 19.2 s | 213.670 MB/s | 0.2 % | 75.5 % | | Random Read 1000 MBs | 8.3 s | 119.860 MB/s | 0.1 % | 37.8 % | `----------------------------------------------------------------------' Tiotest latency results: ,-------------------------------------------------------------------------. | Item | Average latency | Maximum latency | % >2 sec | % >10 sec | +--------------+-----------------+-----------------+----------+-----------+ | Write | 4.544 ms | 904.253 ms | 0.00000 | 0.00000 | | Random Write | 14.281 ms | 76.098 ms | 0.00000 | 0.00000 | | Read | 4.676 ms | 23.379 ms | 0.00000 | 0.00000 | | Random Read | 8.324 ms | 95.415 ms | 0.00000 | 0.00000 | |--------------+-----------------+-----------------+----------+-----------| | Total | 5.923 ms | 904.253 ms | 0.00000 | 0.00000 | `--------------+-----------------+-----------------+----------+-----------' oakley [/var/tmp/tiobench-0.3.3](SHARK)(10)> ./tiotest -R -d /dev/md0 -t 1 -b 1048575 -f 4096 Tiotest results for 1 concurrent io threads: ,----------------------------------------------------------------------. | Item | Time | Rate | Usr CPU | Sys CPU | +-----------------------+----------+--------------+----------+---------+ | Write 4096 MBs | 41.3 s | 99.128 MB/s | 0.0 % | 22.6 % | | Random Write 1000 MBs | 17.3 s | 57.768 MB/s | 0.1 % | 12.8 % | | Read 4096 MBs | 18.0 s | 227.463 MB/s | 0.2 % | 73.1 % | | Random Read 1000 MBs | 8.8 s | 113.064 MB/s | 0.1 % | 34.1 % | `----------------------------------------------------------------------' Tiotest latency results: ,-------------------------------------------------------------------------. | Item | Average latency | Maximum latency | % >2 sec | % >10 sec | +--------------+-----------------+-----------------+----------+-----------+ | Write | 9.943 ms | 95.471 ms | 0.00000 | 0.00000 | | Random Write | 16.422 ms | 138.189 ms | 0.00000 | 0.00000 | | Read | 4.392 ms | 16.970 ms | 0.00000 | 0.00000 | | Random Read | 8.825 ms | 47.702 ms | 0.00000 | 0.00000 | |--------------+-----------------+-----------------+----------+-----------| | Total | 8.238 ms | 138.189 ms | 0.00000 | 0.00000 | `--------------+-----------------+-----------------+----------+-----------' ./tiotest -R -d /dev/raw/raw1 -t 1 -b 1048576 -f 4096 Tiotest results for 1 concurrent io threads: ,----------------------------------------------------------------------. | Item | Time | Rate | Usr CPU | Sys CPU | +-----------------------+----------+--------------+----------+---------+ | Write 4096 MBs | 33.5 s | 122.205 MB/s | 0.0 % | 13.2 % | | Random Write 1000 MBs | 16.9 s | 59.202 MB/s | 0.0 % | 5.2 % | | Read 4096 MBs | 27.0 s | 151.801 MB/s | 0.0 % | 12.8 % | | Random Read 1000 MBs | 10.2 s | 98.126 MB/s | 0.0 % | 8.8 % | `----------------------------------------------------------------------' Tiotest latency results: ,-------------------------------------------------------------------------. | Item | Average latency | Maximum latency | % >2 sec | % >10 sec | +--------------+-----------------+-----------------+----------+-----------+ | Write | 8.181 ms | 129.457 ms | 0.00000 | 0.00000 | | Random Write | 16.887 ms | 135.257 ms | 0.00000 | 0.00000 | | Read | 6.586 ms | 13.119 ms | 0.00000 | 0.00000 | | Random Read | 10.188 ms | 93.608 ms | 0.00000 | 0.00000 | |--------------+-----------------+-----------------+----------+-----------| | Total | 8.591 ms | 135.257 ms | 0.00000 | 0.00000 | `--------------+-----------------+-----------------+----------+-----------' ./tiotest -R -d /dev/md0 -t 1 -b 1048576 -f 4096 Tiotest results for 1 concurrent io threads: ,----------------------------------------------------------------------. | Item | Time | Rate | Usr CPU | Sys CPU | +-----------------------+----------+--------------+----------+---------+ | Write 4096 MBs | 16.5 s | 248.086 MB/s | 0.3 % | 55.3 % | | Random Write 1000 MBs | 8.1 s | 123.448 MB/s | 0.1 % | 25.6 % | | Read 4096 MBs | 17.6 s | 232.478 MB/s | 0.2 % | 76.3 % | | Random Read 1000 MBs | 8.4 s | 119.276 MB/s | 0.0 % | 37.2 % | `----------------------------------------------------------------------' Tiotest latency results: ,-------------------------------------------------------------------------. | Item | Average latency | Maximum latency | % >2 sec | % >10 sec | +--------------+-----------------+-----------------+----------+-----------+ | Write | 3.411 ms | 332.483 ms | 0.00000 | 0.00000 | | Random Write | 5.788 ms | 460.008 ms | 0.00000 | 0.00000 | | Read | 4.297 ms | 14.304 ms | 0.00000 | 0.00000 | | Random Read | 8.375 ms | 14.837 ms | 0.00000 | 0.00000 | |--------------+-----------------+-----------------+----------+-----------| | Total | 4.487 ms | 460.008 ms | 0.00000 | 0.00000 | `--------------+-----------------+-----------------+----------+-----------' RESULTS FROM 2.6.0-test11 kernel ./tiotest -d /movie -t 1 -b 1048575 -f 4096 Tiotest results for 1 concurrent io threads: ,----------------------------------------------------------------------. | Item | Time | Rate | Usr CPU | Sys CPU | +-----------------------+----------+--------------+----------+---------+ | Write 4096 MBs | 21.0 s | 195.424 MB/s | 0.1 % | 44.4 % | | Random Write 1000 MBs | 10.5 s | 95.033 MB/s | 0.0 % | 16.0 % | | Read 4096 MBs | 24.3 s | 168.458 MB/s | 0.1 % | 38.9 % | | Random Read 1000 MBs | 7.9 s | 126.029 MB/s | 0.1 % | 26.7 % | `----------------------------------------------------------------------' Tiotest latency results: ,-------------------------------------------------------------------------. | Item | Average latency | Maximum latency | % >2 sec | % >10 sec | +--------------+-----------------+-----------------+----------+-----------+ | Write | 4.125 ms | 415.368 ms | 0.00000 | 0.00000 | | Random Write | 9.259 ms | 93.033 ms | 0.00000 | 0.00000 | | Read | 5.933 ms | 30.779 ms | 0.00000 | 0.00000 | | Random Read | 7.929 ms | 27.271 ms | 0.00000 | 0.00000 | |--------------+-----------------+-----------------+----------+-----------| | Total | 5.729 ms | 415.368 ms | 0.00000 | 0.00000 | `--------------+-----------------+-----------------+----------+-----------' ./tiotest -R -d /dev/md0 -t 1 -b 1048575 -f 4096 Tiotest results for 1 concurrent io threads: ,----------------------------------------------------------------------. | Item | Time | Rate | Usr CPU | Sys CPU | +-----------------------+----------+--------------+----------+---------+ | Write 4096 MBs | 29.9 s | 136.782 MB/s | 0.0 % | 24.0 % | | Random Write 1000 MBs | 12.9 s | 77.349 MB/s | 0.1 % | 14.6 % | | Read 4096 MBs | 23.9 s | 171.733 MB/s | 0.1 % | 41.6 % | | Random Read 1000 MBs | 9.5 s | 105.334 MB/s | 0.1 % | 26.4 % | `----------------------------------------------------------------------' Tiotest latency results: ,-------------------------------------------------------------------------. | Item | Average latency | Maximum latency | % >2 sec | % >10 sec | +--------------+-----------------+-----------------+----------+-----------+ | Write | 6.598 ms | 155.516 ms | 0.00000 | 0.00000 | | Random Write | 9.014 ms | 161.239 ms | 0.00000 | 0.00000 | | Read | 5.820 ms | 23.064 ms | 0.00000 | 0.00000 | | Random Read | 9.487 ms | 23.564 ms | 0.00000 | 0.00000 | |--------------+-----------------+-----------------+----------+-----------| | Total | 6.806 ms | 161.239 ms | 0.00000 | 0.00000 | `--------------+-----------------+-----------------+----------+-----------' ./tiotest -R -d /dev/raw/raw1 -t 1 -b 1048576 -f 4096 Tiotest results for 1 concurrent io threads: ,----------------------------------------------------------------------. | Item | Time | Rate | Usr CPU | Sys CPU | +-----------------------+----------+--------------+----------+---------+ | Write 4096 MBs | 17.1 s | 240.096 MB/s | 0.0 % | 6.0 % | | Random Write 1000 MBs | 10.4 s | 95.943 MB/s | 0.0 % | 2.5 % | | Read 4096 MBs | 14.2 s | 289.157 MB/s | 0.0 % | 10.0 % | | Random Read 1000 MBs | 9.4 s | 106.827 MB/s | 0.0 % | 3.4 % | `----------------------------------------------------------------------' Tiotest latency results: ,-------------------------------------------------------------------------. | Item | Average latency | Maximum latency | % >2 sec | % >10 sec | +--------------+-----------------+-----------------+----------+-----------+ | Write | 4.164 ms | 17.062 ms | 0.00000 | 0.00000 | | Random Write | 10.421 ms | 33.531 ms | 0.00000 | 0.00000 | | Read | 3.457 ms | 11.822 ms | 0.00000 | 0.00000 | | Random Read | 9.359 ms | 28.052 ms | 0.00000 | 0.00000 | |--------------+-----------------+-----------------+----------+-----------| | Total | 5.003 ms | 33.531 ms | 0.00000 | 0.00000 | `--------------+-----------------+-----------------+----------+-----------' ./tiotest -R -d /dev/md0 -t 1 -b 1048576 -f 4096 Tiotest results for 1 concurrent io threads: ,----------------------------------------------------------------------. | Item | Time | Rate | Usr CPU | Sys CPU | +-----------------------+----------+--------------+----------+---------+ | Write 4096 MBs | 21.1 s | 193.962 MB/s | 0.0 % | 41.6 % | | Random Write 1000 MBs | 7.0 s | 142.856 MB/s | 0.1 % | 31.4 % | | Read 4096 MBs | 30.1 s | 136.219 MB/s | 0.1 % | 30.8 % | | Random Read 1000 MBs | 11.1 s | 89.860 MB/s | 0.0 % | 21.3 % | `----------------------------------------------------------------------' Tiotest latency results: ,-------------------------------------------------------------------------. | Item | Average latency | Maximum latency | % >2 sec | % >10 sec | +--------------+-----------------+-----------------+----------+-----------+ | Write | 4.340 ms | 270.506 ms | 0.00000 | 0.00000 | | Random Write | 1.720 ms | 2.968 ms | 0.00000 | 0.00000 | | Read | 7.277 ms | 26.267 ms | 0.00000 | 0.00000 | | Random Read | 10.869 ms | 23.652 ms | 0.00000 | 0.00000 | |--------------+-----------------+-----------------+----------+-----------| | Total | 5.904 ms | 270.506 ms | 0.00000 | 0.00000 | `--------------+-----------------+-----------------+----------+-----------' From the above results it looks like they are getting better performance on all shares except raw, really peaking out on the md's to the 230mb/s range. So this is specifically a raw only issue. -----2.4.21----------------2.6.0-test11------------ /movie \ /movie 213.670 MB/s \ 168.458 MB/s 119.860 MB/s \ 126.029 MB/s /dev/md0 \ /dev/md0 227.463 MB/s \ 171.733 MB/s 113.064 MB/s \ 105.334 MB/s /dev/raw/raw1 \ /dev/raw/raw1 151.801 MB/s \ 289.157 MB/s 98.126 MB/s \ 106.827 MB/s /dev/md0 \ /dev/md0 232.478 MB/s \ 136.219 MB/s 119.276 MB/s \ 89.860 MB/s
I'm pretty sure this is a dup of 104633, marking it as such. *** This bug has been marked as a duplicate of 104633 ***
The customer is not able to test out the fix you gave. Please see the comments from them - We tried installing both the kernel RPM as provided, and rolling a new kernel RPM from the SRPM, and, in both cases, there are unresolved symbols that prevent the system from booting from the SCSI drive (scsi being one of the unresolved symbols). The symbol is timer pending. Do you have a new kernel? I gave them the kernel-smp from the url you mentioned.
An errata has been issued which should help the problem described in this bug report. This report is therefore being closed with a resolution of ERRATA. For more information on the solution and/or where to find the updated files, please follow the link below. You may reopen this bug report if the solution does not work for you. http://rhn.redhat.com/errata/RHSA-2004-188.html