incubator-cassandra-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Aaron Morton <aa...@thelastpickle.com>
Subject Re: Cassandra 1.1.6 - Disk usage and Load displayed in ring doesn't match
Date Wed, 18 Dec 2013 03:23:43 GMT
-tmp- files will sit in the data dir, if there was an error creating them during compaction
or flushing to disk they will sit around until a restart. 

Check the logs for errors to see if compaction was failing on something.

Cheers

-----------------
Aaron Morton
New Zealand
@aaronmorton

Co-Founder & Principal Consultant
Apache Cassandra Consulting
http://www.thelastpickle.com

On 17/12/2013, at 12:28 pm, Narendra Sharma <narendra.sharma@gmail.com> wrote:

> No snapshots.
> 
> I restarted the node and now the Load in ring is in sync with the disk usage. Not sure
what caused it to go out of sync. However, the Live SStable count doesn't match exactly with
the number of data files on disk.
> 
> I am going through the Cassandra code to understand what could be the reason for the
mismatch in the sstable count and also why there is no reference of some of the data files
in system.log.
> 
> 
> 
> 
> On Mon, Dec 16, 2013 at 2:45 PM, Arindam Barua <abarua@247-inc.com> wrote:
>  
> 
> Do you have any snapshots on the nodes where you are seeing this issue?
> 
> Snapshots will link to sstables which will cause them not be deleted.
> 
>  
> 
> -Arindam
> 
>  
> 
> From: Narendra Sharma [mailto:narendra.sharma@gmail.com] 
> Sent: Sunday, December 15, 2013 1:15 PM
> To: user@cassandra.apache.org
> Subject: Cassandra 1.1.6 - Disk usage and Load displayed in ring doesn't match
> 
>  
> 
> We have 8 node cluster. Replication factor is 3. 
> 
>  
> 
> For some of the nodes the Disk usage (du -ksh .) in the data directory for CF doesn't
match the Load reported in nodetool ring command. When we expanded the cluster from 4 node
to 8 nodes (4 weeks back), everything was okay. Over period of last 2-3 weeks the disk usage
has gone up. We increased the RF from 2 to 3 2 weeks ago.
> 
>  
> 
> I am not sure if increasing the RF is causing this issue.
> 
>  
> 
> For one of the nodes that I analyzed:
> 
> 1. nodetool ring reported load as 575.38 GB
> 
>  
> 
> 2. nodetool cfstats for the CF reported:
> 
> SSTable count: 28
> 
> Space used (live): 572671381955
> 
> Space used (total): 572671381955
> 
>  
> 
>  
> 
> 3. 'ls -1 *Data* | wc -l' in the data folder for CF returned
> 
> 46
> 
>  
> 
> 4. 'du -ksh .' in the data folder for CF returned
> 
> 720G
> 
>  
> 
> The above numbers indicate that there are some sstables that are obsolete and are still
occupying space on disk. What could be wrong? Will restarting the node help? The cassandra
process is running for last 45 days with no downtime. However, because the disk usage is high,
we are not able to run full compaction.
> 
>  
> 
> Also, I can't find reference to each of the sstables on disk in the system.log file.
For eg I have one data file on disk as (ls -lth):
> 
> 86G Nov 20 06:14
> 
>  
> 
> I have system.log file with first line:
> 
> INFO [main] 2013-11-18 09:41:56,120 AbstractCassandraDaemon.java (line 101) Logging initialized
> 
>  
> 
> The 86G file must be a result of some compaction. I see no reference of data file in
system.log file between 11/18 to 11/25. What could be the reason for that? The only reference
is dated 11/29 when the file was being streamed to another node (new node).
> 
>  
> 
> How can I identify the obsolete files and remove them? I am thinking about following.
Let me know if it make sense.
> 
> 1. Restart the node and check the state.
> 
> 2. Move the oldest data files to another location (to another mount point)
> 
> 3. Restart the node again
> 
> 4. Run repair on the node so that it can get the missing data from its peers.
> 
>  
> 
>  
> 
> I compared the numbers of a healthy node for the same CF:
> 
> 1. nodetool ring reported load as 662.95 GB
> 
>  
> 
> 2. nodetool cfstats for the CF reported:
> 
> SSTable count: 16
> 
> Space used (live): 670524321067
> 
> Space used (total): 670524321067
> 
>  
> 
> 3. 'ls -1 *Data* | wc -l' in the data folder for CF returned
> 
> 16
> 
>  
> 
> 4. 'du -ksh .' in the data folder for CF returned
> 
> 625G
> 
>  
> 
>  
> 
> -Naren
> 
>  
> 
> 
> 
>  
> 
> -- 
> Narendra Sharma
> 
> Software Engineer
> 
> http://www.aeris.com
> 
> http://narendrasharma.blogspot.com/
> 
>  
> 
> 
> 
> 
> -- 
> Narendra Sharma
> Software Engineer
> http://www.aeris.com
> http://narendrasharma.blogspot.com/
> 


Mime
View raw message