Messages in this thread | | | Date | Tue, 23 May 2006 07:37:01 +0000 | From | "Rainer Shiz" <> | Subject | Re: RAID Sync Speeds |
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Thanks Neil and Chris for your quick replies.
Neil, well when you say 'detectable activity' what do you exactly refer to. Because my system is for all purposes 'idle'. It is not on the network, just booted it up, no apps running, only linux got booted and I am logging in through console (text only mode - no X). So I wish the sync speeds were atleast somewhere inbetween min and max values. But I see it hovering around min (min being 5000, speed was around 5320 kb/s). My max was around 250000.
But once I changed min value to 20000, my speeds were around 10000kb/s. Max being same 250000. I heard that speed values are averaged out for about 5 minutes or so. Hence I did try these experiments for about 1 hour each.
This is what made me wonder if there is anything in the 2.6.12 kernel which is causing this behavior!
One more question while I am at it, if a RAID Set is newly created and syncing, and now I change the /proc/sys/dev/raid/speed_limit_min and max values will this reflect on new RAID Sets that are created henceforth or even the existing RAID Sets which are being synced currently?
And Chris, you are right - I understand that doing any other extraneous disk I/o or fetching will cause the sync speeds to slow down or in the extreme case there will be a limit on the SATA bus and how many other hard disks share it and what i/o is happening on them too, but in my case I am running these experiments keeping this in mind and keeping all hard disk activity at almost zero levels.
And yes, I am too using Seagate hard drives. Does mixing up of hard drives (vendors) affect this sync process.? (I presume not but please correct me if I am wrong).
Thanks again. Rainer
On 5/22/06, Neil Brown <neilb@suse.de> wrote: > On Monday May 22, rainer.shiz@gmail.com wrote: > > > > So Is the 2.6 kernel designed to sync at speeds closer to min than max? > > > > If there is other detectable activity, the sync speed will be kept at > or below the min. > If there no other activity, the sync speed will be kept at or below > the max. > > NeilBrown > - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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