No space on device while using osm2postgresql (with PBF file)

I am running osm2postgresql on an Ubuntu virtual machine (EC2 micro instance) using the instructions provided on the wiki.

Everything runs fine but I get the following error after the program has been running for a long time:

Mar 04, 2014 2:42:31 PM org.openstreetmap.osmosis.core.pipeline.common.ActiveTaskManager waitForCompletion
FINE: Waiting for task 1-read-pbf to complete.
Mar 04, 2014 3:29:56 PM org.openstreetmap.osmosis.core.pipeline.common.ActiveTaskManager waitForCompletion
SEVERE: Thread for task 1-read-pbf failed
org.openstreetmap.osmosis.core.OsmosisRuntimeException: An output error has occurred, aborting.
        at org.openstreetmap.osmosis.core.store.DataPostbox.checkForOutputErrors(DataPostbox.java:78)
        at org.openstreetmap.osmosis.core.store.DataPostbox.populateCentralQueue(DataPostbox.java:134)
        at org.openstreetmap.osmosis.core.store.DataPostbox.put(DataPostbox.java:184)
        at org.openstreetmap.osmosis.core.buffer.v0_6.EntityBuffer.process(EntityBuffer.java:38)
        at crosby.binary.osmosis.OsmosisBinaryParser.parseWays(OsmosisBinaryParser.java:172)
        at crosby.binary.BinaryParser.parse(BinaryParser.java:121)
        at crosby.binary.BinaryParser.handleBlock(BinaryParser.java:68)
        at crosby.binary.file.FileBlock.process(FileBlock.java:135)
        at crosby.binary.file.BlockInputStream.process(BlockInputStream.java:34)
        at crosby.binary.osmosis.OsmosisReader.run(OsmosisReader.java:37)
        at java.lang.Thread.run(Thread.java:744)

Mar 04, 2014 3:29:56 PM org.openstreetmap.osmosis.pgsnapshot.common.CopyFileWriter release
SEVERE: Unable to close writer.
java.io.IOException: No space left on device
        at java.io.FileOutputStream.writeBytes(Native Method)
        at java.io.FileOutputStream.write(FileOutputStream.java:345)
        at java.io.BufferedOutputStream.Mar 04, 2014 3:29:57 PM org.openstreetmap.osmosis.core.pipeline.common.ActiveTaskManager waitForCompletion
SEVERE: Thread for task 2-buffer failed
org.openstreetmap.osmosis.core.OsmosisRuntimeException: Unable to write value (SRID=4326;POLYGON((-93.2169649 44.9913991,-93.2169649 44.9914236,-93.2169311 44.9914236,-93.2169311 44.9913991,-93.2169649 44.9913991)))
        at org.openstreetmap.osmosis.pgsnapshot.common.CopyFileWriter.writeField(CopyFileWriter.java:253)
        at org.openstreetmap.osmosis.pgsnapshot.v0_6.impl.CopyFilesetBuilder.process(CopyFilesetBuilder.java:187)
        at org.openstreetmap.osmosis.core.container.v0_6.WayContainer.process(WayContainer.java:60)
        at org.openstreetmap.osmosis.pgsnapshot.v0_6.impl.CopyFilesetBuilder.process(CopyFilesetBuilder.java:115)
        at org.openstreetmap.osmosis.pgsnapshot.v0_6.PostgreSqlDumpWriter.process(PostgreSqlDumpWriter.java:58)
        at org.openstreetmap.osmosis.core.buffer.v0_6.EntityBuffer.run(EntityBuffer.java:74)
        at java.lang.Thread.run(Thread.java:744)
Caused by: java.io.IOException: No space left on device
        at java.io.FileOutputStream.writeBytes(Native Method)
        at java.io.FileOutputStream.write(FileOutputStream.java:345)
        at java.io.BufferedOutputStream.flushBuffer(BufferedOutputStream.java:82)
        at java.io.BufferedOutputStream.write(BufferedOutputStream.java:126)
        at sun.nio.cs.StreamEncoder.writeBytes(StreamEncoder.java:221)
        at sun.nio.cs.StreamEncoder.implWrite(StreamEncoder.java:282)
        at sun.nio.cs.StreamEncoder.write(StreamEncoder.java:125)
        at java.io.OutputStreamWriter.write(OutputStreamWriter.java:207)
        at java.io.BufferedWriter.flushBuffer(BufferedWriter.java:129)
        at java.io.BufferedWriter.write(BufferedWriter.java:230)
        at java.io.Writer.write(Writer.java:157)
        at org.openstreetmap.osmosis.pgsnapshot.common.CopyFileWriter.writeField(CopyFileWriter.java:249)
        ... 6 more

Mar 04, 2014 3:29:57 PM org.openstreetmap.osmosis.core.pipeline.common.PassiveTaskManager waitForCompletion
FINE: Task 3-write-pgsql-dump is passive, no completion wait required.
Mar 04, 2014 3:29:57 PM org.openstreetmap.osmosis.core.Osmosis main
SEVERE: Execution aborted.
org.openstreetmap.osmosis.core.OsmosisRuntimeException: One or more tasks failed.
        at org.openstreetmap.osmosis.core.pipeline.common.Pipeline.waitForCompletion(Pipeline.java:146)
        at org.openstreetmap.osmosis.core.Osmosis.run(Osmosis.java:92)
        at org.openstreetmap.osmosis.core.Osmosis.main(Osmosis.java:37)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:606)
        at org.codehaus.plexus.classworlds.launcher.Launcher.launchStandard(Launcher.java:329)
        at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:239)
        at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:409)
        at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:352)
        at org.codehaus.classworlds.Launcher.main(Launcher.java:47)

Error 1. The command which triggered the error was:
./$osmosis_version/bin/osmosis -v --read-$filetype file="$osmfile" --buffer --write-pgsql-dump enableBboxBuilder=yes enableLinestringBuilder=yes nodeLocationStoreType="TempFile" directory="$temporarydir"
on line 435 of the osm2postgresql script.
## To delete the imported or temporary data, you might need to
 ## run something similar to this (use with care the lines with the '*'):
 # To remove osmosis temporary data:
 rm osmosis-0.40.tgz
 rm -r osmosis-0.40/
 rm -r ./tempgis
 # To delete the imported data, you may need to run:
 dropdb -p 5432 gis
 # If you created a tablespace:
 echo "DROP TABLESPACE ;" | /usr/lib/postgresql/9.1/bin/psql -p 5432
 # If you created a tablespace or used the --install option:
 sudo rm -r /var/lib/postgresql/PostgresPlus/data

Only 20% of the disk space (out of 30 gigs) has been used. How can I resolve this error?