Bug 806405
| Summary: | max_hw_sectors_kb not there in RHS2 | ||
|---|---|---|---|
| Product: | [Red Hat Storage] Red Hat Gluster Storage | Reporter: | Ben England <bengland> |
| Component: | unclassified | Assignee: | Anthony Towns <atowns> |
| Status: | CLOSED CURRENTRELEASE | QA Contact: | M S Vishwanath Bhat <vbhat> |
| Severity: | medium | Docs Contact: | |
| Priority: | medium | ||
| Version: | 2.0 | CC: | amarts, flanagan, gluster-bugs, mzywusko, sghai |
| Target Milestone: | Release Candidate | ||
| Target Release: | RHGS 2.0.0 | ||
| Hardware: | Unspecified | ||
| OS: | Unspecified | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | Bug Fix | |
| Doc Text: | Story Points: | --- | |
| Clone Of: | Environment: | ||
| Last Closed: | 2012-11-13 06:09:02 UTC | Type: | --- |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
| Bug Depends On: | |||
| Bug Blocks: | 817967 | ||
I think to do this we just want to populate /etc/modprobe.d/megaraid_sas.conf in the %pre part of the kickstart; the initramfs should then get generated correctly when the kernel is installed. I'm no anaconda expert, I was just trying to describe the end result, there may well be a much simpler way to get the same result, /sys/block/sdb/queue/max_sectors_kb > 128. megaraid_sas.conf added to /etc/modprobe.d via appliance-base as of build RHS-2.0-20120524.n.0-RHS-x86_64-DVD1.is verified with following rpms by updating RHS-2.0-20120524.n.0-RHS-x86_64-DVD1.iso glusterfs-fuse-3.3.0qa45-1.el6.x86_64 glusterfs-3.3.0qa45-1.el6.x86_64 glusterfs-server-3.3.0qa45-1.el6.x86_64 glusterfs-rdma-3.3.0qa45-1.el6.x86_64 org.apache.hadoop.fs.glusterfs-glusterfs-0.20.2_0.1-1.noarch glusterfs-geo-replication-3.3.0qa45-1.el6.x86_64 megaraid_sas.conf is added to /etc/modprobe.d and having : options megaraid_sas max_sectors=2048 --- [root@dhcp201-154 run]# cat /etc/modprobe.d/megaraid_sas.conf options megaraid_sas max_sectors=2048 [root@dhcp201-154 run]# cd [root@dhcp201-154 ~]# cd /etc/modprobe.d/ [root@dhcp201-154 modprobe.d]# ls anaconda.conf dist-alsa.conf dist-oss.conf blacklist.conf dist.conf megaraid_sas.conf [root@dhcp201-154 modprobe.d]# ls | grep megaraid_sas.conf megaraid_sas.conf [root@dhcp201-154 modprobe.d]# -- I did not see this problem anymore in RHS-2.0-20120530-something.iso, I think you can close this bug When I checked this for Anshi build dated March 20, I did not see /etc/modprobe.d/megaraid_sas.conf in place, and the max_hw_sectors_kb was 280 on gprfs041.sbu.lab.eng.bos.redhat.com. I tried to fix using same procedure as before, adding /etc/modprobe.d/megaraid_sas.conf with line options megaraid_sas max_sectors=2048 and re-running dracut utility to remake /boot/initramfs for my kernel. I then saw this error from dmesg: megasas: INIT adapter done megasas: max_sectors should be > 0and <= 560 (or < 1MB for GEN2 controller) So what I'm saying is that we may want to remove this optimization which worked for older megaraid controllers but apparently will not work for newer ones. This is disappointing because at 1 GB/sec throughput, 280 KB = 280 usec, not much time for Linux to process an I/O request. max_sectors_kb was set to max_hw_sectors_kb, which is the maximum that this driver will support, it appears. |
Description of problem: We need to tune the block device parameter max_hw_sectors_kb, which is important getting the I/O request size high enough to fully exploit the hardware RAID controller and many drives behind it. Specifically, we need to raise max_hw_sectors_kb, which requires /opt/modprobe.d/megaraid_sas.conf containing: options megaraid_sas max_sectors=2048 then rebuild initramfs as follows # cd boot # dracut initramfs-2.6.32-220.7.1.el6.x86_64.img.new 2.6.32-220.7.1.el6.x86_64 # mv initramfs-2.6.32-220.7.1.el6.x86_64.im{g,g.orig} # initramfs-2.6.32-220.7.1.el6.x86_64.im{g.new,g} # reboot I think anaconda script should be able to do this, particularly the initramfs generation, or maybe the .iso could be set up with the right initramfs to begin with. Version-Release number of selected component (if applicable): RHS 2 beta How reproducible: always