Bug 48422
| Summary: | Slow raid and scsi function | ||
|---|---|---|---|
| Product: | [Retired] Red Hat Linux | Reporter: | Need Real Name <cl> |
| Component: | kernel | Assignee: | Arjan van de Ven <arjanv> |
| Status: | CLOSED WORKSFORME | QA Contact: | David Lawrence <dkl> |
| Severity: | high | Docs Contact: | |
| Priority: | low | ||
| Version: | 7.1 | ||
| Target Milestone: | --- | ||
| Target Release: | --- | ||
| Hardware: | i586 | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | Bug Fix | |
| Doc Text: | Story Points: | --- | |
| Clone Of: | Environment: | ||
| Last Closed: | 2003-06-06 14:28:03 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: | |||
Get faster hardware? :) The problem is with your method of benchmarking. I too get a slightly slower hdparm -t time on a raid0 array (six devices) than I do from an individual disk in the array. I attribute this to the overhead that the RAID code has compared to direct disk access. However, if I do something slightly more realistic (timing a 'dd' of a 256M file from the same raid0 array compared to a single hard disk), the raid0 array wins The kernel panic is something that is bad and a more specific problem than "it's too slow" - I am reassigning this bug to the kernel in hopes that you will provide the maintainers with details of that problem. A few questions for the performance first: * what stride-size did you set the raid0 to ? * could you use the tiobench program (http://sourceforge.net/projects/tiobench ) instead of hdparm as that will test FILE access and not raw io access. (the kernel will do things like readahead on files, not on devices) * what kernel version did you try ? 2.4.2-2 or 2.4.3-12 ? You mention a "panic". Any chance of gettin any info of that so we can try to find the bug ? Closing idle bug |
From Bugzilla Helper: User-Agent: Mozilla/4.72 [en] (X11; U; SunOS 5.6 sun4u) Description of problem: Raid systems seem to have problems. How reproducible: Always Steps to Reproduce: 0. hdparm -t /dev/sda1 1.18 MBps 1. set up stock raidtab with 2 scsi drives From the Software Raid HOW-TO. 2. mkraid /dev/md0 3. mkfs /dev/md0 4. hdparm -t /dev/md0 600 KBps Actual Results: Raid was slower that the single drive. When I take the raid 0 to 6 drives data rate drops to around 100KBps. When attempting to move data to the 6 disk raid0 drive the kernel will panic. The effect worsens with the use of raid 4 and raid 5. Expected Results: I would expect a faster response time from a raid0 config with 2 drives and and much faster response time from a raid0 with 6 drives. Additional info: System: 1 P100 64 Megs Ram 1.6 gig IDE HD AHA1542 Scsi Card 7 IBM 1050m scsi drives System : 2 P166 64 megs Ram 1.05 gig IDE HD AHA1542 SCSI Card 7 IBM 1050m scsi drives I have been doing raid testing on RH7.1 I have yet to see it work worth a flip. Cards tested 2 AHA1542, AHA2920,2 FDomain 18xxx cards I have also tested on the 7 IBM drives, 4 Quantum, 5 Seagate, 3 Conner drives (all scsi).