Resending if anyone has ideas.. On Tue, Apr 28, 2015 at 3:32 PM, Raghuram BK <[email protected]> wrote:
> > I've been trying to figure out the performance overhead of gluster over > the underlying filesystem and find the difference to be quite stark. Is > this normal? Can something be done about it? I've tried to eliminate the > network overhead by doing everything locally and eliminate the effect of > caching by forcing hits to the hard drives.. Here's what I did : > > 1. Force the underlying filesystem(ZFS) to always read from disk > 2. Create the underlying storage (zfs create frzpool/normal/d1) > 3. Create a gluster distributed volume with only one brick on the local > machine. (gluster volume create g1 > fractalio-pri.fractalio.lan:/frzpool/normal/d1 force) > 4. Start it (gluster volume start g1) > 5. Check the volume info : > > [root@fractalio-pri fractalio]# gluster v info g1 > > Volume Name: g1 > Type: Distribute > Volume ID: e50f13d2-cb98-47f4-8113-3f15b4b6306a > Status: Started > Number of Bricks: 1 > Transport-type: tcp > Bricks: > Brick1: fractalio-pri.fractalio.lan:/frzpool/normal/d1 > > 6. Mount it (mount -t glusterfs localhost:/g1 /mnt/g1) > 7. Populate a test file into the volume : > > [root@fractalio-pri fractalio]# dd if=/dev/zero of=/mnt/g1/ddfile1 bs=1M > count=2000 > 2000+0 records in > 2000+0 records out > 2097152000 bytes (2.1 GB) copied, 8.4938 s, 247 MB/s > > 8. Read the file from the gluster mount : > > [root@fractalio-pri fractalio]# dd if=/mnt/g1/ddfile1 of=/dev/zero bs=1M > 2000+0 records in > 2000+0 records out > 2097152000 bytes (2.1 GB) copied, 84.4174 s, 24.8 MB/s > > 9. Read the file directly from the underlying storage : > > [root@fractalio-pri fractalio]# dd if=/frzpool/normal/d1/ddfile1 > of=/dev/zero bs=1M > 2000+0 records in > 2000+0 records out > 2097152000 bytes (2.1 GB) copied, 24.722 s, 84.8 MB/s > > > The throughput comes down from 84.8MB/s to 24.8MB/s, a 240% overhead?! > -- *Fractalio Data, India* Mobile: +91 96635 92022 Email: [email protected] <[email protected]> Web: www.fractalio.com
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