Thanks for the reply Aaron. By compaction being on, do you mean if run
nodetool compact, then the answer is no. I haven't set any explicit
compaction_thresholds which means it should be using the default, min 4 and
max 32. Having said that to solve the problem, I just did a full cluster
restart and ran nodetool repair again. The entire cluster of 6 nodes was
repaired in 10 hours. I am also contemplating since all the 6 nodes are
replicas of each other, do I even need to run repair on all the nodes.
Wouldn't running it on the first node suffice since it will repair all the
ranges its responsible for(which is everything). So unless I upgrade to
1.0.+, where I can use the -pr option is it advisable to just run repair on
the first node.
-Raj
On Tue, May 22, 2012 at 5:05 AM, aaron morton aa...@thelastpickle.comwrote:
I also dont understand if all these nodes are replicas of each other why
is that the first node has almost double the data.
Have you performed any token moves ? Old data is not deleted unless you
run nodetool cleanup.
Another possibility is things like a lot of hints. Admittedly it would
have to be a *lot* of hints.
The third is that compaction has fallen behind.
This week its even worse, the nodetool repair has been running for the
last 15 hours just on the first node and when I run nodetool
compactionstats I constantly see this -
pending tasks: 3
First check the logs for errors.
Repair will first calculate the differences, you can see this as a
validation compaction in nodetool compactionstats.
Then it will stream the data, you can watch that with nodetool netstats.
Try to work out which part is taking the most time. 15 hours for 50Gb
sounds like a long time (btw do you have compaction on ?)
Cheers
-
Aaron Morton
Freelance Developer
@aaronmorton
http://www.thelastpickle.com
On 20/05/2012, at 3:14 AM, Raj N wrote:
Hi experts,
I have a 6 node cluster spread across 2 DCs.
DC RackStatus State LoadOwnsToken
113427455640312814857969558651062452225
DC1 RAC13 Up Normal 95.98 GB33.33% 0
DC2 RAC5Up Normal 50.79 GB0.00% 1
DC1 RAC18 Up Normal 50.83 GB33.33%
56713727820156407428984779325531226112
DC2 RAC7Up Normal 50.74 GB0.00%
56713727820156407428984779325531226113
DC1 RAC19 Up Normal 61.72 GB33.33%
113427455640312814857969558651062452224
DC2 RAC9Up Normal 50.83 GB0.00%
113427455640312814857969558651062452225
They are all replicas of each other. All reads and writes are done at
LOCAL_QUORUM. We are on Cassandra 0.8.4. I see that our weekend nodetool
repair runs for more than 12 hours. Especially on the first one which has
96 GB data. Is this usual? We are using 500 GB SAS drives with ext4 file
system. This gets worse every week. This week its even worse, the nodetool
repair has been running for the last 15 hours just on the first node and
when I run nodetool compactionstats I constantly see this -
pending tasks: 3
and nothing else. Looks like its just stuck. There's nothing substantial
in the logs as well. I also dont understand if all these nodes are replicas
of each other why is that the first node has almost double the data. Any
help will be really appreciated.
Thanks
-Raj
