I noticed this on an m1.xlarge (cassandra 1.1.10) instance today as well, 1 or 2 disks in a raid 0 running at 85 to 100% the others 35 to 50ish.
Have not looked into it. Cheers ----------------- Aaron Morton Freelance Cassandra Consultant New Zealand @aaronmorton http://www.thelastpickle.com On 26/03/2013, at 11:57 PM, Alain RODRIGUEZ <arodr...@gmail.com> wrote: > We use C* on m1.xLarge AWS EC2 servers, with 4 disks xvdb, xvdc, xvdd, xvde > parts of a logical Raid0 (md0). > > I use to see their use increasing in the same way. This morning there was a > normal minor compaction followed by messages dropped on one node (out of 12). > > Looking closely at this node I saw the following: > > http://img69.imageshack.us/img69/9425/opscenterweirddisk.png > > On this node, one of the four disks (xvdd) started working hardly while other > worked less intensively. > > This is quite weird since I always saw this 4 disks being used the exact same > way at every moment (as you can see on 5 other nodes or when the node ".239" > come back to normal). > > Any idea on what happened and on how it can be avoided ? > > Alain
