I have a small EC2 instance running with a 25GB EBS volume attached. It has a database on it that I need to manipulate by doing things like dropping indexes and creating new ones. This is on rather large (multi-GB, millions of rows) tables. After running one DROP INDEX operation that ran all day without finishing, I killed it and tried to see what was going on. Here’s the results of the first 10 minutes of testing:
-bash-3.2# dd if=/dev/zero of=/vol/128.txt bs=128k count=1000 1000+0 records in 1000+0 records out 131072000 bytes (131 MB) copied, 0.818328 seconds, 160 MB/s
This looks great. I’d love to get 160MB/s all the time. But wait! There’s more!
-bash-3.2# dd if=/dev/zero of=/vol/128.txt bs=128k count=100000 dd: writing `/vol/128.txt': No space left on device 86729+0 records in 86728+0 records out 11367641088 bytes (11 GB) copied, 268.191 seconds, 42.4 MB/s
Ok, well… that’s completely miserable. Let’s try …
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