On a single spindle: $ time dd if=/dev/zero of=bigfile bs=8k count=2000000 2000000+0 records in 2000000+0 records out
real 2m8.569s user 0m0.725s sys 0m19.633s None of my drives are partitioned big enough for me to create 2x RAM sized files on a single disk. I have 16MB RAM and only 36GB drives. But here are some number for my 12-disk lvm2 striped volume. $ time dd if=/dev/zero of=bigfile3 bs=8k count=4000000 4000000+0 records in 4000000+0 records out real 1m17.059s user 0m1.479s sys 0m41.293s Mark On Thu, 21 Jul 2005 16:14:47 -0700 "Luke Lonergan" <[EMAIL PROTECTED]> wrote: > Cool! > > At what rate does your disk setup write sequential data, e.g.: > time dd if=/dev/zero of=bigfile bs=8k count=500000 > > (sized for 2x RAM on a system with 2GB) > > BTW - the Compaq smartarray controllers are pretty broken on Linux from a > performance standpoint in our experience. We've had disastrously bad > results from the SmartArray 5i and 6 controllers on kernels from 2.4 -> > 2.6.10, on the order of 20MB/s. > > For comparison, the results on our dual opteron with a single LSI SCSI > controller with software RAID0 on a 2.6.10 kernel: > > [EMAIL PROTECTED] dbfast]$ time dd if=/dev/zero of=bigfile bs=8k > count=500000 > 500000+0 records in > 500000+0 records out > > real 0m24.702s > user 0m0.077s > sys 0m8.794s > > Which calculates out to about 161MB/s. > > - Luke > > > On 7/21/05 2:55 PM, "Mark Wong" <[EMAIL PROTECTED]> wrote: > > > I just ran through a few tests with the v14 patch against 100GB of data > > from dbt3 and found a 30% improvement; 3.6 hours vs 5.3 hours. Just to > > give a few details, I only loaded data and started a COPY in parallel > > for each the data files: > > http://www.testing.osdl.org/projects/dbt3testing/results/fast_copy/ > > > > Here's a visual of my disk layout, for those familiar with the database > > schema: > > http://www.testing.osdl.org/projects/dbt3testing/results/fast_copy/layout-dev4 > > -010-dbt3.html > > > > I have 6 arrays of fourteen 15k rpm drives in a split-bus configuration > > attached to a 4-way itanium2 via 6 compaq smartarray pci-x controllers. > > > > Let me know if you have any questions. > > > > Mark > > > ---------------------------(end of broadcast)--------------------------- TIP 1: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
