Re: More testing: 4x parallel 2G writes, sequential reads

Andreas Dilger wrote: > The test shows ext4 finishing marginally faster in the write case, and > marginally slower in the read case. What happens if you have 4 parallel > readers? http://people.redhat.com/esandeen/seekwatcher/ext4_4_thread_par_read.png http://people.redhat.com/esandeen/seekwatch

Re: More testing: 4x parallel 2G writes, sequential reads

Shapor Naghibzadeh wrote: > On Wed, Nov 07, 2007 at 04:42:59PM -0600, Eric Sandeen wrote: >> Again this was on a decent HW raid so seek penalties are probably not >> too bad. > > You may want to verify that by doing a benchmark on the raw device. I > recently did some benchmarks doing random I/O

Re: More testing: 4x parallel 2G writes, sequential reads

On Wed, Nov 07, 2007 at 04:42:59PM -0600, Eric Sandeen wrote: > Again this was on a decent HW raid so seek penalties are probably not > too bad. You may want to verify that by doing a benchmark on the raw device. I recently did some benchmarks doing random I/O on a Dell 2850 w/ a PERC (megaraid)

Re: More testing: 4x parallel 2G writes, sequential reads

Hi, could you try to larger preallocation? like 512/1024/2048 blocks, please? thanks, Alex Eric Sandeen wrote: I tried ext4 vs. xfs doing 4 parallel 2G IO writes in 1M units to 4 different subdirectories of the root of the filesystem: http://people.redhat.com/esandeen/seekwatcher/ext4_4_threa

Re: More testing: 4x parallel 2G writes, sequential reads

Andreas Dilger wrote: > The question is what the "best" result is for this kind of workload? > In HPC applications the common case is that you will also have the data > files read back in parallel instead of serially. Agreed, I'm not trying to argue what's better or worse, I'm just seeing what it

Re: More testing: 4x parallel 2G writes, sequential reads

On Nov 07, 2007 16:42 -0600, Eric Sandeen wrote: > I tried ext4 vs. xfs doing 4 parallel 2G IO writes in 1M units to 4 > different subdirectories of the root of the filesystem: > > http://people.redhat.com/esandeen/seekwatcher/ext4_4_threads.png > http://people.redhat.com/esandeen/seekwatcher/xfs

More testing: 4x parallel 2G writes, sequential reads

I tried ext4 vs. xfs doing 4 parallel 2G IO writes in 1M units to 4 different subdirectories of the root of the filesystem: http://people.redhat.com/esandeen/seekwatcher/ext4_4_threads.png http://people.redhat.com/esandeen/seekwatcher/xfs_4_threads.png http://people.redhat.com/esandeen/seekwatcher