every other day I do full backups to both a second internal disk and an external usb disk. I am using a fully up to date centos 5.1 AMD 64 X2 6400+ machine. with SATA disks. using an NVIDIA chipset, when I do a full rsync the responsiveness of my machine suffers. Slow on the internal disk and really slow on external usb. doing "top" shows 0% idle but only 17% CPU usage by the rsync command. I am stunned that a 6400+ machine dual core can get this sluggish when doing a copy to disk. Is there something I potentially have not set right? dmesg shows my SATA disks at UDMA133 and 1.5 Gbps. THanks, Jerry
Jerry Geis wrote:> every other day I do full backups to both a second internal disk and > an external usb disk. > > I am using a fully up to date centos 5.1 AMD 64 X2 6400+ machine. with > SATA disks. > using an NVIDIA chipset, > > when I do a full rsync the responsiveness of my machine suffers. Slow > on the internal disk and really slow on external usb. > doing "top" shows 0% idle but only 17% CPU usage by the rsync command. > > I am stunned that a 6400+ machine dual core can get this sluggish when > doing a copy to disk. > Is there something I potentially have not set right? > > dmesg shows my SATA disks at UDMA133 and 1.5 Gbps. > > THanks, > > Jerry > _______________________________________________ > CentOS mailing list > CentOS at centos.org > http://lists.centos.org/mailman/listinfo/centos >Hi I would recommend you install the systat rpm and then use sar and iostat commands to see if you can identify where the bottleneck is occurring. Have a nice day
Jerry Geis wrote:> every other day I do full backups to both a second internal disk and an > external usb disk. > > I am using a fully up to date centos 5.1 AMD 64 X2 6400+ machine. with > SATA disks. > using an NVIDIA chipset, > > when I do a full rsync the responsiveness of my machine suffers. Slow on > the internal disk and really slow on external usb. > doing "top" shows 0% idle but only 17% CPU usage by the rsync command. > > I am stunned that a 6400+ machine dual core can get this sluggish when > doing a copy to disk. > Is there something I potentially have not set right? > > dmesg shows my SATA disks at UDMA133 and 1.5 Gbps.Rsync works by transferring the entire directory listing, then wading through the whole thing, so there is a certain memory overhead per file in the set. If your file list is huge you might be running out of RAM. Otherwise you are just waiting for the disk heads to seek since they won't be where you want them for responsiveness when they are traversing the whole disk for comparisons. -- Les Mikesell lesmikesell at gmail.com
> I would recommend you install the systat rpm and then use sar and > iostat commands to see if you can identify where the bottleneck is > occurring. > >I installed sysstat and played with it a little - wasnt getting anywhere. I did some looking last night and came across a kernel tweak echo 10 > /proc/sys/vm/swappiness This has help the responsiveness during the rsync to the external USB drive which was the worst case. Thanks, Jerry