In my opinion, this isn't a real issue. I don't see the real problem behind this. Turning a disk to full is an eventual behavior.
Any real concern behind this? - Sijie On Thu, May 18, 2017 at 9:30 AM, Charan Reddy G <reddychara...@gmail.com> wrote: > As part of BOOKKEEPER-643 ( > https://github.com/apache/bookkeeper/commit/694568b0ff0d048c284c8d5db0c945 > 5d30dfa3ce), > "entryLogFilePreallocationEnabled" logic is introduced in > EntryLogger.java. > > Because of this logic, preallocated entryLogChannel will be used as a newly > created logchannel even though the ledgerDir, in which it is created, is > full. > > Consider the following example - > > 1) We have configured Bookies with two LedgerDirs - 'ledgerDir1', > 'ledgerDir2' > 2) lets say current active channel in EntryLogger is 'logChannel1' which is > created in 'ledgerDir1' > 3) since 'entryLogFilePreallocationEnabled' is enabled by default, when we > set 'logChannel1' as the current active channel, we create async task to > create a new logChannel for future purpose (check > allocatorExecutor.submit(allocateNewLog task)) > 4) currently both the ledgerDirs are in writable state, so for precreation > of new logchannel it might pick any ledgerdir > 5) lets say it chose 'ledgerDir1' again for the creation of new logchannel > - 'logChannel2' > 6) now lets assume ledgerDir1 is full, in that case shouldCreateNewEntryLog > will be set to true > 7) if a new entry is added to entrylogger, then since > shouldCreateNewEntryLog is set to true, it will close the current active > logchannel - 'logChannel1' and add it to logChannelsToFlush list. > 8) For new logChannel it will get the preallocated log - 'logChannel2' and > will continue to use it as current active channel, though 'ledgerDir1' is > not writable anymore. > > relevant code snippets in EntryLogger.java > > private LedgerDirsListener getLedgerDirsListener() { > return new LedgerDirsListener() { > @Override > public void diskFull(File disk) { > // If the current entry log disk is full, then create new > entry > // log. > if (currentDir != null && currentDir.equals(disk)) { > shouldCreateNewEntryLog.set(true); > } > } > > @Override > public void diskAlmostFull(File disk) { > // If the current entry log disk is almost full, then > create new entry > // log. > if (currentDir != null && currentDir.equals(disk)) { > shouldCreateNewEntryLog.set(true); > } > } > .... > } > > synchronized long addEntry(long ledger, ByteBuffer entry, boolean > rollLog) throws IOException { > ..... > boolean createNewLog = shouldCreateNewEntryLog.get(); > if (createNewLog || reachEntryLogLimit) { > if (doRegularFlushes) { > flushCurrentLog(); > } > createNewLog(); > // Reset the flag > if (createNewLog) { > shouldCreateNewEntryLog.set(false); > } > } > ..... > } > > > synchronized BufferedLogChannel createNewLog() throws IOException { > BufferedLogChannel bc; > if (!entryLogPreAllocationEnabled || null == preallocation) { > // initialization time to create a new log > bc = allocateNewLog(); > } else { > // has a preallocated entry log > try { > bc = preallocation.get(); > ... > preallocation = allocatorExecutor.submit(new > Callable<BufferedLogChannel>() { > @Override > public BufferedLogChannel call() throws IOException { > return allocateNewLog(); > } > }); > } > LOG.info("Created new entry logger {}.", bc.getLogId()); > return bc; > } > > Thanks, > Charan >
