cassandra-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Johan Elmerfjord <jelme...@adobe.com>
Subject Re: 1.0.8 with Leveled compaction - Possible issues
Date Fri, 16 Mar 2012 13:41:30 GMT
Perfect.. this helped a lot - and I can confirm that I have run in to
the same issue as described in:
http://mail-archives.apache.org/mod_mbox/cassandra-user/201203.mbox/%
3CCALqbeQbQ=d-hORVhA-LHOo_a5j46fQrsZMm+OQgfkgR=4RRQJQ@mail.gmail.com%3E

Where it goes down when it tries to move up files to a higher level -
that is out of bounds.

Nice that I could get a overview of the levels by looking in
the .json-file as well.

Any timeframe on when we can expect 1.0.9 to be released?

/Johan


-- 
  
Johan Elmerfjord | Sr. Systems Administration/Mgr, EMEA | Adobe Systems,
Product Technical Operations | p. +45 3231 6008 | x86008 | cell. +46 735
101 444 | Jelmerfj@adobe.com 

On Thu, 2012-03-15 at 17:00 -0700, Watanabe Maki wrote:
> update column family with LCS option + upgradesstables should convert
> all of your sstables.
> Set lig4j config:
> org.apache.cassandra.db.compaction=DEBUG
> in conf/log4j-server.properties and retry your procedure to find what
> is happen.
> 
> 
> maki
> 
> 
> 
> On 2012/03/16, at 7:05, Johan Elmerfjord <jelmerfj@adobe.com> wrote:
> 
> 
> 
> > Hi, I'm testing the community-version of Cassandra 1.0.8.
> > We are currently on 0.8.7 in our production-setup.
> > 
> > We have 3 Column Families that each takes between 20 and 35 GB on
> > disk per node. (8*2 nodes total)
> > We would like to change to Leveled Compaction - and even try
> > compression as well to reduce the space needed for compactions.
> > We are running on SSD-drives as latency is a key-issue.
> > 
> > As test I have imported one Column Family from 3 production-nodes to
> > a 3 node test-cluster.
> > The data on the 3 nodes ranges from 19-33GB. (with at least one
> > large SSTable (Tiered size - recently compacted)).
> > 
> > After loading this data to the 3 test-nodes, and running scrub and
> > repair, I took a backup of the data so I have good test-set of data
> > to work on.
> > Then I changed changed to leveled compaction, using the
> > cassandra-cli:
> > 
> > UPDATE COLUMN FAMILY TestCF1 WITH
> > compaction_strategy=LeveledCompactionStrategy;
> > I could see the change being written to the logfile on all nodes.
> > 
> > Then I don't know for for sure if I need to run anything else to
> > make the change happen - or if it's just to wait.
> > My test-cluster does not receive new data.
> > 
> > For this  KS & CF and on each of the nodes I have tried some or
> > several of: upgradesstable, scrub, compact, cleanup and repair -
> > each task taking between 40 minutes and 4 hours.
> > With the exception of compact that returns almost immediately with
> > no visible compactions made.
> > 
> > On some node I ended up with over 30000 files with the default 5MB
> > size for leveled compaction, on another node it didn't look like
> > anything has been done and I still have a 19GB SSTable.
> > 
> > I then made another change.
> > UPDATE COLUMN FAMILY TestCF1 WITH
> > compaction_strategy=LeveledCompactionStrategy AND
> > compaction_strategy_options=[{sstable_size_in_mb: 64}];
> > WARNING: [{}] strategy_options syntax is deprecated, please use {}
> > Which is probably wrong in the documentation - and should be:
> > UPDATE COLUMN FAMILY TestCF1 WITH
> > compaction_strategy=LeveledCompactionStrategy AND
> > compaction_strategy_options={sstable_size_in_mb: 64};
> > 
> > I think that we will be able to find the data in 3 searches with a
> > 64MB size - and still only use around 700MB while doing compactions
> > - and keep the number of files ~3000 per CF.
> > 
> > A few days later it looks like I still have a mix between original
> > huge SStables, 5MB once - and some nodes has 64MB files as well.
> > Do I need to do something special to clean this up?
> > I have tried another scrub /upgradesstables/clean - but nothing
> > seems to do any change to me.
> > 
> > Finally I have also tried to enable compression:
> > UPDATE COLUMN FAMILY TestCF1 WITH
> > compression_options=[{sstable_compression:SnappyCompressor,
> > chunk_length_kb:64}];
> > - which results in the same [{}] - warning.
> > 
> > As you can see below - this created CompressionInfo.db - files on
> > some nodes - but not on all.
> > 
> > Is there a way I can force Teired sstables to be converted into
> > Leveled once - and then to compression as well?
> > Why are the original file (Tiered Sized SSTables still present on
> > testnode1 - when is it supposed to delete them?
> > 
> > Can I change back and forth between compression (on/off - or
> > chunksizes) - and between Leveled vs Size Tiered compaction?
> > Is there a way to see if the node is done - or waiting for
> > something?
> > When is it safe to apply another setting - does it have to complete
> > one reorg before moving on to the next?
> > 
> > Any input or own experiences are warmly welcome.
> > 
> > Best regards, Johan
> > 
> > 
> > Some lines of example directory-listings below.:
> > 
> > Some files for testnode 3. (looks like it's still have the original
> > Size Tiered files around, and a mixture of compressed 64MB files -
> > and 5MB files? 
> > 
> > total 19G
> > drwxr-xr-x 3 cass cass 4.0K Mar 13 17:11 snapshots
> > -rw-r--r-- 1 cass cass 6.0G Mar 13 18:42 TestCF1-hc-6346-Index.db
> > -rw-r--r-- 1 cass cass 1.3M Mar 13 18:42 TestCF1-hc-6346-Filter.db
> > -rw-r--r-- 1 cass cass  13G Mar 13 18:42 TestCF1-hc-6346-Data.db
> > -rw-r--r-- 1 cass cass 2.4M Mar 13 18:42 TestCF1-hc-6346-CompressionInfo.db
> > -rw-r--r-- 1 cass cass 4.3K Mar 13 18:42 TestCF1-hc-6346-Statistics.db
> > -rw-r--r-- 1 cass cass 195K Mar 13 18:42 TestCF1-hc-6347-Filter.db
> > -rw-r--r-- 1 cass cass 4.9M Mar 13 18:42 TestCF1-hc-6347-Index.db
> > -rw-r--r-- 1 cass cass 9.0M Mar 13 18:42 TestCF1-hc-6347-Data.db
> > -rw-r--r-- 1 cass cass 4.3K Mar 13 18:42 TestCF1-hc-6347-Statistics.db
> > -rw-r--r-- 1 cass cass 2.0K Mar 13 18:42 TestCF1-hc-6347-CompressionInfo.db
> > -rw-r--r-- 1 cass cass  11K Mar 13 18:43 TestCF1-hc-6351-CompressionInfo.db
> > -rw-r--r-- 1 cass cass  52M Mar 13 18:43 TestCF1-hc-6351-Data.db
> > -rw-r--r-- 1 cass cass 1.1M Mar 13 18:43 TestCF1-hc-6351-Filter.db
> > -rw-r--r-- 1 cass cass  28M Mar 13 18:43 TestCF1-hc-6351-Index.db
> > -rw-r--r-- 1 cass cass 4.3K Mar 13 18:43 TestCF1-hc-6351-Statistics.db
> > -rw-r--r-- 1 cass cass  401 Mar 13 18:43 TestCF1.json
> > -rw-r--r-- 1 cass cass  950 Mar 13 18:43 TestCF1-hc-6350-CompressionInfo.db
> > -rw-r--r-- 1 cass cass 4.3M Mar 13 18:43 TestCF1-hc-6350-Data.db
> > -rw-r--r-- 1 cass cass  93K Mar 13 18:43 TestCF1-hc-6350-Filter.db
> > -rw-r--r-- 1 cass cass 2.3M Mar 13 18:43 TestCF1-hc-6350-Index.db
> > -rw-r--r-- 1 cass cass 4.3K Mar 13 18:43 TestCF1-hc-6350-Statistics.db
> > -rw-r--r-- 1 cass cass  400 Mar 13 18:43 TestCF1-old.json
> > 
> > 
> > 
> > Some DB-files ordered by size for testnode1:
> > No compressed files - but has the original Size-tiered files - as
> > well as 5MB Leveled compaction-files - but no 64 MB once. 
> > 
> > total 83G
> > -rw-r--r-- 1 cass cass   33G Mar 13 07:14 TestCF1-hc-33504-Data.db
> > -rw-r--r-- 1 cass cass   11G Mar 13 07:14 TestCF1-hc-33504-Index.db
> > -rw-r--r-- 1 cass cass  407M Mar 13 07:14 TestCF1-hc-33504-Filter.db
> > -rw-r--r-- 1 cass cass  5.1M Mar 13 05:27 TestCF1-hc-33338-Data.db
> > -rw-r--r-- 1 cass cass  5.1M Mar 13 08:54 TestCF1-hc-38997-Data.db
> > -rw-r--r-- 1 cass cass  5.1M Mar 13 07:15 TestCF1-hc-33513-Data.db
> > 
> > 
> > 
> > -- 
> >   
> > Johan Elmerfjord | Sr. Systems Administration/Mgr, EMEA | Adobe
> > Systems, Product Technical Operations | p. +45 3231 6008 | x86008 |
> > cell. +46 735 101 444 | Jelmerfj@adobe.com 
> > 
> > 

Mime
View raw message