On Mon, Mar 8, 2010 at 5:17 AM, Jon Masters <jonathan@xxxxxxxxxxxxxx> wrote: > I recommend this approach. The SATA disk is drastically faster than the > original very legacy IDE on the Ultra 5. The use of a flash disk is very > reliable (in theory, anyway) and I can even use eSATA if I want to, or > the faster IDE or SATA ports on the SATA PCI upgrade card. Hi, I can provide you some troughput statistics that will hopefully show you a bit what to expect. SATA indeed gives you a lot of speed but there are some things to consider and not get your hopes up too much. My system: - Ultra 5, 440Mh CPU, 512MB RAM. sda: Maxtor 80GB ATA drive connected to c0t0 (internal IDE controler). The internal IDE controller goes up to MWDMA2, which gves you around 16MB/s according to the standards. sda: multi word DMA 2 (16MB/s) (EXT3 filesystem) [root@medusa slowdrive]# dd if=/dev/zero of=myfile.txt bs=4096 count=250000 250000+0 records in 250000+0 records out 1024000000 bytes (1.0 GB) copied, 61.2546 s, 16.7 MB/s sda: multi word DMA 2 (16MB/s) with RAID1 layer [root@medusa mnt]# dd if=/dev/zero of=myfile.txt bs=4096 count=250000 250000+0 records in 250000+0 records out 1024000000 bytes (1.0 GB) copied, 62.3785 s, 16.4 MB/s sda: multi word DMA 2 (16MB/s) with RAID1 layer and LVM layer [root@medusa mnt]# dd if=/dev/zero of=myfile.txt bs=4096 count=250000 250000+0 records in 250000+0 records out 1024000000 bytes (1.0 GB) copied, 63.119 s, 16.2 MB/s What you can see above is that your performance bottleneck is the IDE bus with the poor MWDMA2 capabilities. However, whatever you decide to do, RAID, LVM or RAID + LVM, you will always get the full speed. sdc: Maxtor 1TB SATA disc connected to a Silicon Image 3512 PCI card. The kernel configured this with UDMA100 (100MB/s) sdc: Ultra DMA 100 (with EXT3 FS) [root@medusa /]# dd if=/dev/zero of=myfile.txt bs=4096 count=250000 250000+0 records in 250000+0 records out 1024000000 bytes (1.0 GB) copied, 23.9389 s, 42.8 MB/s sdb: Maxtor 1TB SATA disc connected t a Silicon Image 3512 PCI card. The kernel configured this with UDMA100 (100MB/s) sdb: Ultra DMA 100 with RAID 1 layer [root@medusa mnt]# dd if=/dev/zero of=myfile.txt bs=4096 count=250000 250000+0 records in 250000+0 records out 1024000000 bytes (1.0 GB) copied, 39.9939 s, 25.6 MB/s sdb: Ultra DMA 100 with LVM layer [root@medusa mnt]# dd if=/dev/zero of=myfile.txt bs=4096 count=250000 250000+0 records in 250000+0 records out 1024000000 bytes (1.0 GB) copied, 35.3786 s, 28.9 MB/s sdb: Ultra DMA 100 with RAID 1 and LVM layer [root@medusa mnt]# dd if=/dev/zero of=myfile.txt bs=4096 count=250000 250000+0 records in 250000+0 records out 1024000000 bytes (1.0 GB) copied, 38.5377 s, 26.6 MB/s Above shows that when you use SATA on an Ultra 5 you get way better speeds than with your IDE disc but not what you would get on a faster sparc. My guess is that eventhough you use UDMA, the troughput is just to much for the CPU. This becomes more clear when you use RAID or LVM volumes, where you can see a decrease of 20MB/s when either RAID or LVM is used. Also keep in mind that these tests were from /dev/zero to the filesystem. An rsync from sdb to sdc (SATA to SATA) was very disapointing. Still LVM/RAID on SATA will give you a better performance than when you use IDE just don't expect wonders. An rsync from sdb to sdc for example went with 320KB/s... Patrick _______________________________________________ sparc mailing list sparc@xxxxxxxxxxxxxxxxxxxxxxx https://admin.fedoraproject.org/mailman/listinfo/sparc
