Cable problems, I suspect this is more to ones liking? platinum:/mnt/config# ./ddtest time dd if=/dev/hda of=/dev/null bs=64k count=10000 10000+0 records in 10000+0 records out 655360000 bytes transferred in 12.050804 seconds (54383093 bytes/sec) real 0m12.058s user 0m0.000s sys 0m1.780s time dd if=/dev/hdc of=/dev/null bs=64k count=10000 10000+0 records in 10000+0 records out 655360000 bytes transferred in 11.508676 seconds (56944865 bytes/sec) real 0m11.510s user 0m0.010s sys 0m1.670s What exactly am I testing here though? I'm only testing write speed not read speed, correct? Is there an analogous test for reads? Thanks Jay ----- Original Message ----- From: "Guy" <bugzilla@xxxxxxxxxxxxxxxx> To: <me@xxxxxxxxxx> Sent: Friday, May 07, 2004 1:24 AM Subject: RE: Sync rates? > I don't understand what's wrong with your disks. If you can, configure one > as a master without a slave. Then time it. > > My disks are slow/old SCSI disks. The max speed is about 19Meg/second. > Today's disks are much faster. > The reason my disks are as slow as 4000-5000K /sec is that I have 7 of them > on a 40M/sec SCSI bus. > I checked my notes, the speed is just over 5000K/sec. > If I were to upgrade the SCSI card to a LVD (80M/sec) I would get about > 10000K/sec. I did that once with a barrowed card. Was very cool. > My disks are Seagate ST118202LC or SX118282LS, depending on where I look! > 18Gig, 10,000RPM. Good seek time, but slow sustained transfer rate. > > Guy > > -----Original Message----- > From: me@xxxxxxxxxx [mailto:me@xxxxxxxxxx] > Sent: Friday, May 07, 2004 1:29 AM > To: Guy; linux-raid@xxxxxxxxxxxxxxx > Subject: Re: Sync rates? > > Weird, seems as if the faster the processor the longer the test takes. I > ran it on 2 other machines, in addition to the one with raid. Here are the > results. What type of disks are you using? Your results are almost twice > as fast as my fastest (which is machine 3 i.e. my slowest chip speed). > > Jay > > Machine 1 (the one in question), AMD 3200, 1 GB RAM, Disks on individual IDE > channels > platinum:~# df > Filesystem 1K-blocks Used Available Use% Mounted on > /dev/md0 19686680 1195512 17491132 7% / > tmpfs 452284 0 452284 0% /dev/shm > /dev/md1 39373624 32844 37340696 1% /opt > /dev/md2 39373624 32848 37340692 1% /home > /dev/md4 14974680 32872 14181136 1% /usr/local > > platinum:~# time dd if=/dev/hda of=/dev/null bs=64k count=10000 > 10000+0 records in > 10000+0 records out > 655360000 bytes transferred in 166.335481 seconds (3939989 bytes/sec) > > real 2m46.336s > user 0m0.004s > sys 2m13.280s > > > platinum:~# time dd if=/dev/hdc of=/dev/null bs=64k count=10000 > 10000+0 records in > 10000+0 records out > 655360000 bytes transferred in 171.632623 seconds (3818388 bytes/sec) > > real 2m51.634s > user 0m0.004s > sys 1m33.162s > > # Machine 2, PII 400 Mhz, the disks are master/slave > meir:~# df > Filesystem 1k-blocks Used Available Use% Mounted on > /dev/hda4 4806936 1220040 3342708 27% / > /dev/hda1 46636 935 43293 3% /boot > /dev/hda5 4996728 938156 3804748 20% /home > /dev/hda6 3937220 2026628 1710588 55% /usr > /dev/hdb2 9843308 8246848 1096440 89% /opt > au:/usr/local/src 29530400 6731216 21299120 25% /usr/local/src > > meir:~# time dd if=/dev/hda of=/dev/null bs=64k count=10000 > 10000+0 records in > 10000+0 records out > > real 2m48.300s > user 0m0.030s > sys 1m49.000s > > Machine 1, PPro 180 Mhz, Master/Slave > abba:~# df > Filesystem 1K-blocks Used Available Use% Mounted on > /dev/hda1 9851308 2534948 6815940 28% / > tmpfs 258204 0 258204 0% /dev/shm > /dev/hda3 7842996 3502032 3942552 48% /mnt/hda3 > > > abba:~# time dd if=/dev/hda of=/dev/null bs=64k count=10000 > 10000+0 records in > 10000+0 records out > 655360000 bytes transferred in 56.396242 seconds (11620632 bytes/sec) > > real 0m56.416s > user 0m0.120s > sys 0m11.960s > > > > ----- Original Message ----- > From: "Guy" <bugzilla@xxxxxxxxxxxxxxxx> > To: <me@xxxxxxxxxx> > Sent: Thursday, May 06, 2004 9:44 PM > Subject: RE: Sync rates? > > > > My system re-builds at 4000-5000K/sec/disk. It has 14 disks. > > During a re-build the CPU load is below 5%. > > I have 2 CPUs, P3-500Mhz, 512Meg ram. > > During a re-build I don't notice any slowdown. I had a disk fail and it > > re-build on the spare. I did not know until hours after it was done. > > > > If you cat /proc/mdstat it will show the re-build rate. > > That rate is per disk, not an overall total. > > > > I would say your system has problems! > > Test each disk with dd. > > This is a read test!! > > > > time dd if=/dev/hda of=/dev/null bs=64k count=10000 > > > > This should take less than a minute (34.6 seconds for me). > > If the above gives the same results on each disk, drop the count=10000. > > > > time dd if=/dev/hda of=/dev/null bs=64k > > > > Without the count=10000 it will read 100% of the disk, this may take an > hour > > or more. > > It will report a record count. > > Do this math to determine the speed in K per second. > > Records*64/number of seconds > > > > Replace "hda" with whatever is correct for you. > > Do this for each disk. > > I bet you find 1 disk is much slower than the others. > > Maybe a bad cable, don't know. > > > > Good luck, > > Guy > > > > -----Original Message----- > > From: linux-raid-owner@xxxxxxxxxxxxxxx > > [mailto:linux-raid-owner@xxxxxxxxxxxxxxx] On Behalf Of me@xxxxxxxxxx > > Sent: Thursday, May 06, 2004 10:02 PM > > To: Paul Clements > > Cc: linux-raid@xxxxxxxxxxxxxxx > > Subject: Re: Sync rates? > > > > My machine was idle during the rebuild. When I say idle, I mean no one > > logged in, no user processes running (except me sshed into the box), no > > database, no I/O other than the rebuild. > > > > While the rebuild was going on my system was debilitated, totally slow to > > respond to ssh commands > > > > Jay > > ----- Original Message ----- > > From: "Paul Clements" <paul.clements@xxxxxxxxxxxx> > > To: <me@xxxxxxxxxx> > > Cc: <linux-raid@xxxxxxxxxxxxxxx> > > Sent: Thursday, May 06, 2004 2:59 PM > > Subject: Re: Sync rates? > > > > > > > me@xxxxxxxxxx wrote: > > > > > > > platinum:~# cat /proc/sys/dev/raid/speed_limit_min > > > > 1000 > > > > platinum:~# cat /proc/sys/dev/raid/speed_limit_max > > > > 200000 > > > > Are these acceptable? > > > > > > Well, those values are in KB/s. And, your resync rate is about: > > > > > > 120000000 / ( 24 * 60 * 60 ) = 1388 KB/s > > > > > > if my calculations are correct. I'd try bumping the min value up to say > > > 10000 and see if that speeds things up. Is there much I/O activity on > > > the system? That will slow down a resync quite a bit, too. > > > > > > -- > > > Paul > > > > > > > > > > - > > To unsubscribe from this list: send the line "unsubscribe linux-raid" in > > the body of a message to majordomo@xxxxxxxxxxxxxxx > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > > > > > > > > > > > - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
