>> -----Original Message----- >> From: Donghui Wen [mailto:dhwen@protegonetworks.com] >> Sent: Saturday, March 22, 2003 4:37 PM >> To: Rechenberg, Andrew; linux-raid@vger.kernel.org >> Subject: Re: 3ware bad write speed. >> >> >> Thanks, Andrew: >> What ATA RAID controllers are you using? Do you have any >> benchmark data >> about sequential write? >> >> Donghui We're actually using SCSI disks attached to Adaptec 39160 SCSI controllers. I then have a monster /etc/raidtab to setup the software RAID arrays and I use mdadm to monitor the arrays for failed disks. We used to use the Dell PERC3/QC (OEM LSI MegaRAID Enterprise 1600) for hardware RAID controllers but in basic tests we could get almost 50% better performance from software RAID. If you want (or have) to use ATA controllers for monetary reasons I'm not really the person to ask :) I have a Promise Ultra100TX2 in my home workstation that works great for my home use, but I have not tested these cards in a production environment. I can't recall off-hand what the sequential writes were from tiobench, but here are some bonnie++ numbers for that 52 SCSI disk array with an 8GB file: Seq. Output (writing) Per Char Block Rewrite K/sec %CPU K/sec %CPU K/sec %CPU ---------------------------------------- 23719 99 129707 99 99141 54 Seq. Input (reading) Per Char Block K/sec %CPU K/sec %CPU ------------------------- 27551 98 301288 63 So with one bonnie++ thread I was getting ~127MB/s sequential writes and ~294MB/s sequential reads. I ran two other tests with the same parameters and the averages over three tests were 128.8MB/s reads and 296.7MB/s reads. The details for these numbers are below: Red Hat Linux 7.3 Kernel 2.4.18-26.7.xbigmem with md-seq_file and LVM 1.0.7 patches applied Dell PowerEdge 4600 2x2.4GHz Xeon with HT 4GB RAM 52 15K SCSI disks with equal 17GB partitions 1 RAID10 software RAID array (~442GB usable space) 1 Linux Logical Volume Manager (LVM) Volume Group (VG) on top of the MD device 1 300GB Logical Volume (LV) carved out of the 442GB VG ext3 filesystem on LV (mke2fs -j /dev/vg00/lv00) mounted data=ordered The other portion of the LV was used to test LV snapshots. Let me know if you have any other questions. Thanks, Andy. - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
