Testing ADS Write Speed

Problem: You want to determine how quickly your A3 ADS can write blocks without the use of Alike software.

Solution: Conduct the test below.

The test below will copy block files off the ADS and then back again, using the Linux "time" command to tell us how long it took.

To determine throughput, divide the size of the directory returned in step 3 by the "real" time returned from the test. Be aware that if you have a large ADS, it may not be possible to conduct this test as your A3 local disk may simply lack the space needed. Be sure to check space after step 3.

The steps are:

​1) Drop to the shell (option 4)

2) mkdir blocktest

3) du -hs /mnt/ads/blocks/0aa


5) time cp -r /mnt/ads/blocks/a00 blocktest

6) mkdir /mnt/ads/scratch

7) time cp -r blocktest/a00 /mnt/ads/scratch

This will show us the size of one of the blocks subdirs and the time it takes to copy it locally and then copy it back. This will give us a rough-and-ready idea of block throughput, assuming the size of the blocks subdir is nontrivial and over a couple of GB. If it's too large, it will fill up your local disk, so please do check the results of 3) before proceeding.

After testing is concluded, feel free to delete the test dirs you created:

rm -fr /home/alike/blocktest

rm -fr /mnt/ads/scratch