Friday, September 18, 2015

12,290,000 V.92 dial-up modems...

It's that time of year for a new fast file system.

Here's a single box teaser with a pair of disks that we are building...
echo 1 > /proc/sys/vm/swappiness

mdadm -C /dev/md0 --level=raid0 --raid-devices=2 /dev/disk0 /dev/disk1

mke2fs -E nodiscard /dev/md0

mount /dev/md0 /mnt/test

time dd if=/dev/zero of=/mnt/test/cuff1.dat bs=1024k count=100000 oflag=direct &
time dd if=/dev/zero of=/mnt/test/cuff2.dat bs=1024k count=100000 oflag=direct &
time dd if=/dev/zero of=/mnt/test/cuff3.dat bs=1024k count=100000 oflag=direct &
time dd if=/dev/zero of=/mnt/test/cuff4.dat bs=1024k count=100000 oflag=direct &
time dd if=/dev/zero of=/mnt/test/cuff5.dat bs=1024k count=100000 oflag=direct &
time dd if=/dev/zero of=/mnt/test/cuff6.dat bs=1024k count=100000 oflag=direct &
time dd if=/dev/zero of=/mnt/test/cuff7.dat bs=1024k count=100000 oflag=direct &
time dd if=/dev/zero of=/mnt/test/cuff8.dat bs=1024k count=100000 oflag=direct &

du -sh /mnt/test/cuff*
98G     /mnt/test/cuff1.dat
98G     /mnt/test/cuff2.dat
98G     /mnt/test/cuff3.dat
98G     /mnt/test/cuff4.dat
98G     /mnt/test/cuff5.dat
98G     /mnt/test/cuff6.dat
98G     /mnt/test/cuff7.dat
98G     /mnt/test/cuff8.dat

Gives me this for writing out about 0.8 of a terabyte in parallel:

Eight threads @ 3.6GB/s

104857600000 bytes (105 GB) copied, 233.532 s, 449 MB/s
104857600000 bytes (105 GB) copied, 233.652 s, 447 MB/s
104857600000 bytes (105 GB) copied, 233.671 s, 449 MB/s
104857600000 bytes (105 GB) copied, 233.732 s, 450 MB/s
104857600000 bytes (105 GB) copied, 233.758 s, 449 MB/s
104857600000 bytes (105 GB) copied, 233.658 s, 449 MB/s
104857600000 bytes (105 GB) copied, 233.604 s, 448 MB/s
104857600000 bytes (105 GB) copied, 233.371 s, 449 MB/s


And gives me this for reading it all back in:

Eight threads @ 5.4GB/s

104857600000 bytes (105 GB) copied, 155.801 s, 673 MB/s
104857600000 bytes (105 GB) copied, 155.628 s, 674 MB/s
104857600000 bytes (105 GB) copied, 155.577 s, 674 MB/s
104857600000 bytes (105 GB) copied, 155.526 s, 674 MB/s
104857600000 bytes (105 GB) copied, 155.325 s, 675 MB/s
104857600000 bytes (105 GB) copied, 155.323 s, 675 MB/s
104857600000 bytes (105 GB) copied, 154.346 s, 679 MB/s
104857600000 bytes (105 GB) copied, 153.967 s, 681 MB/s


We have 16 of these "things", with enough IB network attached so should get a 57GB/s write 86GB/s read, or the same bandwidth as twelve million v.92 (56K) dial-up modems.

Yep, this isn't your grandpappys flash disk ;-)



[any opinions here are all mine, and have absolutely nothing to do with my employer]
(c) 2011 James Cuff