Hi , On Sun, Mar 15, 2009 at 6:08 AM, Florian Forster < rrdt...@nospam.verplant.org> wrote:
> Hi, > > On Sat, Mar 14, 2009 at 12:01:42PM +0800, lily wrote: > >> Recently I use the rrdtool to create about 12 thousand rrd-file, and > >> update them in 30s . > > > the important metric here is updates per second. Updating 12k RRD files > > every 30 seconds qeuals 400 updates per second. In my experience, you > > can expect about 120-150 updates per second from decent disks. If you > > can stay in memory, you can do significantly more updated of course.. How can I keep the data in memory? Use the mmap ? Is upgrade the version to 1.3.6 wil be OK or I have to something in my code ? My rrdtool is the 1.2.27, I don't know if I upgrade my version to 1.3.6, Is there some *compatibility *problem ? > > > >> [...], and the FS is ext2 > > >> [...], and do the vm Optimizations. But it seems not work. The IO > >> await list is sometime very high. > > > You did mount with `noatime' and `nodiratime', right? While this doesn't > > perform miracles, it'll certainly increase performance some percent.. Yes , I did not do that . But if I do that , I don't have the access time , rigth ? > > > >> Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s rkB/s > wkB/s avgrq-sz avgqu-sz await svctm %util > >> cciss/c0d0 0.00 0.00 0.00 112.44 0.00 907.77 0.00 > 453.89 8.07 112.99 1001.39 9.23 103.73 > > > 450 kBytes/s seems a bit low for a RAID-10 (or RAID-0+1? I keep > > forgetting which one is the one with the better write performance ;) > > setup. With 15k disks you should be able to get as high as > > 1.5 - 2.0 MBytes/s. Can you tell us some more about your system? How > > much RAM do you have? What kind of disks? What are the precise options > > you used when mounting the file system? This kind of stuff.. The await list is very high(1001.39), so the wkB/s is very low (458.89). If the await is very low ( < 3), In my system , a HP 380G5, the wkB/s can be the speed between 30M ~ 40MB. My system is HP 380G5, with 4G RAM . I mount the DISK with no options, use the default. > > > >> The second is sometime when I update the files , there is an error : > >> illegal attempt to update using time 1236857494 when last > update > >> time is 1236857494 (minimum one second step) > >> but I use the timestamp is 1236886011, not the 1236857494. And I > use > >> the rrdtool last to see the last update time of the file , I find the > last > >> update time is 1236857468, also not 1236857494. I have debug a lot of > time , > >> but have no idea about it . > > > I haven't observed this problem yet, but due to misconfiguration by > > users I see this message a lot (when it is legitimate). I see other > > error messages on two machines that are under heavy load though. Such > > messages include: > > > - closing rrd > > - reading the cookie off $FILE faild [sic] > > - is not an RRD file > > > When things go really bad, I get "Unknown CF ''" followed by a SIGFPE. > > > I suspect that the high load on the machines leads to some incomplete > > reads/write which cause these messages/problems. Unfortunately I don't > > have debugging symbols on these machines and no way of getting some onto > > there, so haven't been able to track these problems down yet :/ Now I reduce the number of the file from 12K to 8K , I have not encountered the problem yet. So I think the reason is the high load . > > > Regards, > -octo > -- > Florian octo Forster > Hacker in training > GnuPG: 0x91523C3D > http://verplant.org/ > > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v1.4.6 (GNU/Linux) > > iD4DBQFJvCrfHdggu3Q05IYRAmd3AJiZOH4ACXcE2S9KKM6V/vjSvjEwAJ9PW/0x > 9c2MNqwQGo8Oaxx3YexeVQ== > =8dAd > -----END PGP SIGNATURE----- > > -- Yours Sincerely, lleelm -at- gmail -dot- com
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