stack,

Thanks for your reply, I really appreciate that.

On Fri, Feb 27, 2009 at 11:49 PM, stack <[email protected]> wrote:

> Tell us more about your hbase install?  Number of servers, number of
> regions, schema, general size of your cells and hbase version.


We just have a small hadoop cluster with 1 master and 3 slaves, and 1 single
hmaser and 1 regionserver, and version numbers are both 0.19.


> The configuration that effects most directly the amount of heap used is the
> below:
>
>  <property>
>    <name>hbase.io.index.interval</name>
>    <value>128</value>
>    <description>The interval at which we record offsets in hbase
>    store files/mapfiles.  Default for stock mapfiles is 128.  Index
>    files are read into memory.  If there are many of them, could prove
>    a burden.  If so play with the hadoop io.map.index.skip property and
>    skip every nth index member when reading back the index into memory.
>    Downside to high index interval is lowered access times.
>    </description>
>
> You could try setting io.map.index.skip to 4 or 8 across your cluster and
> restart.
>

We have namenode/secondnamenode/hmaster/regionserver running on a small EC2
instance(1.7G memory).
We think it should be part of the problem, so we switched to a larger
instance now.
We will try above suggestion if we hit the problem again.


>
> The flushing of the cache seems to be frustrated by an hdfs error in the
> below.  You have read the 'getting started' section and have upped your
> ulimit file descriptors?


Yes, we have changed ulimit file descriptors according to the FAQ on the
hbase official site.

Thank you very much.

Regards,
Basil.


>
>
> St.Ack
>
> On Thu, Feb 26, 2009 at 8:16 PM, Xiaogang He <[email protected]> wrote:
>
> > hi,
> >
> > I'm keeping hit following exception after hbase restarted and running a
> > while:
> >
> >        2009-02-26 15:14:04,827 INFO
> > org.apache.hadoop.hbase.regionserver.HLog: Closed
> >
> >
> hdfs://hmaster:50001/hbase/log_10.249.190.85_1235626687854_60020/hlog.dat.1235679079054,
> > entries=100053. New log writer:
> > /hbase/log_10.249.190.85_1235626687854_60020/hlog.dat.1235679244824
> >        2009-02-26 15:14:16,405 INFO
> > org.apache.hadoop.hbase.regionserver.MemcacheFlusher: Forced flushing of
> > 1002_profiles,155123497688845858,1235539496917 because global memcache
> > limit
> > of 396.9m exceeded; currently 396.9m and flushing till 248.1m
> >        2009-02-26 15:14:18,666 INFO
> > org.apache.hadoop.hbase.regionserver.MemcacheFlusher: Forced flushing of
> > 1002_profiles,145928983691898633,1235539496917 because global memcache
> > limit
> > of 396.9m exceeded; currently 386.3m and flushing till 248.1m
> >        2009-02-26 15:14:19,497 INFO
> > org.apache.hadoop.hbase.regionserver.MemcacheFlusher: Forced flushing of
> > 1001_profiles,,1235562106563 because global memcache limit of 396.9m
> > exceeded; currently 376.2m and flushing till 248.1m
> >        2009-02-26 15:14:21,971 INFO
> > org.apache.hadoop.hbase.regionserver.MemcacheFlusher: Forced flushing of
> > 1002_profiles,1859616112140717,1235538938447 because global memcache
> limit
> > of 396.9m exceeded; currently 367.1m and flushing till 248.1m
> >        2009-02-26 15:14:23,506 INFO
> > org.apache.hadoop.hbase.regionserver.MemcacheFlusher: Forced flushing of
> > 1002_profiles,256848350134132138,1235539352160 because global memcache
> > limit
> > of 396.9m exceeded; currently 358.2m and flushing till 248.1m
> >        2009-02-26 15:14:26,273 INFO
> > org.apache.hadoop.hbase.regionserver.MemcacheFlusher: Forced flushing of
> > 1001_profiles,38395253911274047,1235562695944 because global memcache
> limit
> > of 396.9m exceeded; currently 349.4m and flushing till 248.1m
> >        2009-02-26 15:14:27,946 INFO
> > org.apache.hadoop.hbase.regionserver.MemcacheFlusher: Forced flushing of
> > 1001_relationships,18320094988761441,1235659399900 because global
> memcache
> > limit of 396.9m exceeded; currently 340.8m and flushing till 248.1m
> >        2009-02-26 15:14:28,898 INFO
> > org.apache.hadoop.hbase.regionserver.MemcacheFlusher: Forced flushing of
> > 1001_profiles,183105869903093166,1235658588032 because global memcache
> > limit
> > of 396.9m exceeded; currently 332.3m and flushing till 248.1m
> >        2009-02-26 15:14:29,857 INFO
> > org.apache.hadoop.hbase.regionserver.MemcacheFlusher: Forced flushing of
> > 1001_relationships,1279872936511407,1235563047231 because global memcache
> > limit of 396.9m exceeded; currently 323.9m and flushing till 248.1m
> >        2009-02-26 15:14:30,338 INFO
> > org.apache.hadoop.hbase.regionserver.MemcacheFlusher: Forced flushing of
> > 1002_profiles,9374985809090827,1235658787938 because global memcache
> limit
> > of 396.9m exceeded; currently 315.5m and flushing till 248.1m
> >        2009-02-26 15:14:31,284 INFO org.apache.hadoop.hdfs.DFSClient:
> > Exception in createBlockOutputStream java.io.IOException: Bad connect ack
> > with firstBadLink 10.249.187.102:50010
> >        2009-02-26 15:14:31,284 INFO org.apache.hadoop.hdfs.DFSClient:
> > Abandoning block blk_-8226110948737137663_51382
> >        2009-02-26 15:14:39,640 INFO org.apache.hadoop.hdfs.DFSClient:
> > Exception in createBlockOutputStream java.io.IOException: Could not read
> > from stream
> >        2009-02-26 15:14:39,640 INFO org.apache.hadoop.hdfs.DFSClient:
> > Abandoning block blk_4802751471280593846_51382
> >        2009-02-26 15:14:45,807 INFO org.apache.hadoop.hdfs.DFSClient:
> > Exception in createBlockOutputStream java.io.IOException: Bad connect ack
> > with firstBadLink 10.249.187.102:50010
> >        2009-02-26 15:14:45,807 INFO org.apache.hadoop.hdfs.DFSClient:
> > Abandoning block blk_-3919223098697505175_51382
> >        2009-02-26 15:14:51,813 INFO org.apache.hadoop.hdfs.DFSClient:
> > Exception in createBlockOutputStream java.io.IOException: Could not read
> > from stream
> >        2009-02-26 15:14:51,813 INFO org.apache.hadoop.hdfs.DFSClient:
> > Abandoning block blk_-6922144209752436228_51382
> >        2009-02-26 15:14:57,827 WARN org.apache.hadoop.hdfs.DFSClient:
> > DataStreamer Exception: java.io.IOException: Unable to create new block.
> >            at
> >
> >
> org.apache.hadoop.hdfs.DFSClient$DFSOutputStream.nextBlockOutputStream(DFSClient.java:2723)
> >            at
> >
> >
> org.apache.hadoop.hdfs.DFSClient$DFSOutputStream.access$2000(DFSClient.java:1997)
> >            at
> >
> >
> org.apache.hadoop.hdfs.DFSClient$DFSOutputStream$DataStreamer.run(DFSClient.java:2183)
> >
> >        2009-02-26 15:14:57,845 WARN org.apache.hadoop.hdfs.DFSClient:
> Error
> > Recovery for block blk_-6922144209752436228_51382 bad datanode[0] nodes
> ==
> > null
> >        2009-02-26 15:14:57,846 WARN org.apache.hadoop.hdfs.DFSClient:
> Could
> > not get block locations. Aborting...
> >        2009-02-26 15:14:57,924 FATAL
> > org.apache.hadoop.hbase.regionserver.MemcacheFlusher: Replay of hlog
> > required. Forcing server shutdown
> >        org.apache.hadoop.hbase.DroppedSnapshotException: region:
> > 1002_profiles,9374985809090827,1235658787938
> >            at
> >
> >
> org.apache.hadoop.hbase.regionserver.HRegion.internalFlushcache(HRegion.java:896)
> >            at
> > org.apache.hadoop.hbase.regionserver.HRegion.flushcache(HRegion.java:789)
> >            at
> >
> >
> org.apache.hadoop.hbase.regionserver.MemcacheFlusher.flushRegion(MemcacheFlusher.java:227)
> >            at
> >
> >
> org.apache.hadoop.hbase.regionserver.MemcacheFlusher.flushSomeRegions(MemcacheFlusher.java:291)
> >            at
> >
> >
> org.apache.hadoop.hbase.regionserver.MemcacheFlusher.reclaimMemcacheMemory(MemcacheFlusher.java:261)
> >            at
> >
> >
> org.apache.hadoop.hbase.regionserver.HRegionServer.batchUpdates(HRegionServer.java:1614)
> >            at sun.reflect.GeneratedMethodAccessor5.invoke(Unknown Source)
> >            at
> >
> >
> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
> >            at java.lang.reflect.Method.invoke(Method.java:597)
> >            at
> > org.apache.hadoop.hbase.ipc.HBaseRPC$Server.call(HBaseRPC.java:632)
> >            at
> > org.apache.hadoop.hbase.ipc.HBaseServer$Handler.run(HBaseServer.java:895)
> >
> >
> > I noticed there are some parameters regarding this, such as
> > *hbase.regionserver.globalMemcache.upperLimit
> > and **hbase.regionserver.globalMemcache.lowerLimit*.
> >
> > I'm just using the default settings,
> >  <property>
> >    <name>hbase.regionserver.globalMemcache.upperLimit</name>
> >    <value>0.4</value>
> >    <description>Maximum size of all memcaches in a region server before
> new
> >      updates are blocked and flushes are forced. Defaults to 40% of heap.
> >    </description>
> >  </property>
> >  <property>
> >    <name>hbase.regionserver.globalMemcache.lowerLimit</name>
> >    <value>0.25</value>
> >    <description>When memcaches are being forced to flush to make room in
> >      memory, keep flushing until we hit this mark. Defaults to 30% of
> heap.
> >      This value equal to hbase.regionserver.globalmemcache.upperLimit
> > causes
> >      the minimum possible flushing to occur when updates are blocked due
> to
> >      memcache limiting.
> >    </description>
> >  </property>
> >
> > Could anyone please give me some guide to help me out of this issue?
> >
> > Thanks,
> > Basil.
> >
>

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