Ashley M. Kirchner wrote: > > Hi folks. > > I'm posting this to both the Fedora as well as the CentOS lists in > hopes that somewhere, someone can help me figure out what's going on. I > have a dual Xeon 3GHz server that's performing rather slow when it comes > to disk activities. > > The machine is configured with a single 160 GiB OS drive (with CentOS > 5.0) and 4x500 GiB drives setup in a RAID-5 configuration. All drives > are setup for 3.0 GiB SATA link, and the motherboard also supports > that. Looking in dmesg when the system comes up, I see that reflected > as well: > > ata1: SATA link up 3.0 Gbps (SStatus 123 SControl 300) > ata1.00: ATA-7, max UDMA/133, 312581808 sectors: LBA48 NCQ (depth 0/32) > ata1.00: configured for UDMA/133 > scsi1 : ahci > ata2: SATA link up 3.0 Gbps (SStatus 123 SControl 300) > ata2.00: ATA-7, max UDMA/133, 976773168 sectors: LBA48 NCQ (depth 0/32) > ata2.00: configured for UDMA/133 > scsi2 : ahci > ata3: SATA link up 3.0 Gbps (SStatus 123 SControl 300) > ata3.00: ATA-7, max UDMA/133, 976773168 sectors: LBA48 NCQ (depth 0/32) > ata3.00: configured for UDMA/133 > scsi3 : ahci > ata4: SATA link up 3.0 Gbps (SStatus 123 SControl 300) > ata4.00: ATA-7, max UDMA/133, 976773168 sectors: LBA48 NCQ (depth 0/32) > ata4.00: configured for UDMA/133 > scsi4 : ahci > ata5: SATA link up 3.0 Gbps (SStatus 123 SControl 300) > ata5.00: ATA-7, max UDMA/133, 976773168 sectors: LBA48 NCQ (depth 0/32) > ata5.00: configured for UDMA/133 > scsi5 : ahci > > > Now, I don't know what performance numbers *should* be, but on a 1.8 > GiB copy on the RAID (cp from one location to another on the RAID), it > gets done in just under 50 seconds. If I try to delete the folder > afterwards (rm -rf FOLDER) it takes a few seconds to do so, however if I > delete the CONTENTS of the folder, it does so within a fraction of a > second (but then 'sync' takes a few seconds to catch up.) > > That same folder that I'm copying contains 452 jpeg files in it, > ranging from 2.5 to 6.2 MiB. Doing some image processing on them is > where it takes a long time. At the moment I'm doing a simple thumbnail > creation with the ImageMagick suite (convert FILE -thumbnail "200x200>' > `basename FILE .jpg`.th.jpg) and it takes upwards of 8 minutes to > complete. The whole time it's running, 'top' reports the server load as > follows: load average: 1.06, 1.00, 0.81 And the CPU usage is around 9%. > > Interestingly, if I run the same command and have it create .png > instead, it takes longer, but I won't go there just yet. My question > is, is this the expected performance on something like this, or should I > be able to get better results? Is there something I should or could do > to speed up disk based processes? > > Or is this something where it's more memory intensive and I need to > look at adding more (right now it has 2 GiB of memory.) > > > This problem is causing one of our web sites to time out because it's > trying to process hundreds of image files and generate thumbnails, and > it's taking forever to do that. So I'm starting at the bottom of the > pile here, hardware. If it turns out the hardware is fine, and there's > nothing else that can be done to speed it up, then I'll move forward to > other possible culprits, such as the routines within the site scripts > themselves... At first I would suggest against cross-posting. The two OSes are not exactly the same. Also you should specify your exact OS. Regarding the 2 CPUs, do you have the service irqbalance running? Also if not running CentOS 5.0, have you installed the SMP kernel? Regarding parallel processing, I do not know much about GNU/Linux parallelization, however I assume a given script is running on one CPU of the two. Obviously there are others here with more insight about this than me.