flume-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Abraham Fine <...@brightroll.com>
Subject Re: File Channel Backup Checkpoints are I/O Intensive
Date Thu, 03 Jul 2014 00:29:12 GMT
Hari-

I added the new tests and created a new revision to my patch.

https://issues.apache.org/jira/secure/attachment/12653728/compress_backup_checkpoint_new_tests.patch

Thanks,
Abe

-- 
Abraham Fine | Software Engineer
(516) 567-2535
BrightRoll, Inc. | Smart Video Advertising | www.brightroll.com


On Wed, Jul 2, 2014 at 4:32 PM, Hari Shreedharan <hshreedharan@cloudera.com>
wrote:

> Hi Abraham,
>
> In general, the patch looks good. Can you add a couple of tests -
> * Original checkpoint is uncompressed, config changes to compress
> checkpoint - does the file channel restart from original checkpoint? are
> new checkpoints compressed?
> * Compressed checkpoint, config changes to not compress checkpoint - does
> channel start up? are new checkpoints uncompressed?
>
>
> Hari
>
>
>  On Wed, Jul 2, 2014 at 3:06 PM, Abraham Fine <abe@brightroll.com> wrote:
>
>> Hi Brock and Hari-
>>
>> I was just wondering if either of you had a chance to take a look at the
>> patch and if there is anything I can do to improve it.
>>
>> Thanks,
>> Abe
>>
>> --
>> Abraham Fine | Software Engineer
>> (516) 567-2535
>> BrightRoll, Inc. | Smart Video Advertising | www.brightroll.com
>>
>>
>> On Wed, Jun 11, 2014 at 6:48 PM, Brock Noland <brock@cloudera.com> wrote:
>>
>>> This is a great suggestion Abraham!
>>>
>>>
>>> On Wed, Jun 11, 2014 at 5:39 PM, Hari Shreedharan <
>>> hshreedharan@cloudera.com> wrote:
>>>
>>>>  Thanks. I will review it :)
>>>>
>>>>
>>>> Thanks,
>>>> Hari
>>>>
>>>> On Wednesday, June 11, 2014 at 5:00 PM, Abraham Fine wrote:
>>>>
>>>> I went ahead and created a JIRA and patch:
>>>> https://issues.apache.org/jira/browse/FLUME-2401
>>>>
>>>> The option is configurable with:
>>>> agentX.channels.ch1.compressBackupCheckpoint = true
>>>>
>>>> As per your recommendation, I used snappy-java. I also considered the
>>>> snappy and lz4 implementations in Hadoop IO but noticed that the
>>>> Hadoop IO dependency was removed in
>>>> https://issues.apache.org/jira/browse/FLUME-1285
>>>>
>>>> Thanks,
>>>> Abe
>>>> --
>>>> Abraham Fine | Software Engineer
>>>> (516) 567-2535
>>>> BrightRoll, Inc. | Smart Video Advertising | www.brightroll.com
>>>>
>>>>
>>>> On Mon, Jun 9, 2014 at 4:01 PM, Hari Shreedharan
>>>> <hshreedharan@cloudera.com> wrote:
>>>>
>>>> Hi Abraham,
>>>>
>>>> Compressing the backup checkpoint is very possible. Since the backup is
>>>> rarely read (only if the original one is corrupt on restarts), is it
>>>> used.
>>>> So I think compressing it using something like Snappy would make sense
>>>> (GZIP
>>>> might hit performance). Can you try using snappy-java and see if that
>>>> gives
>>>> good perf and reasonable compression?
>>>>
>>>> Patches are always welcome. I’d be glad to review and commit it. I would
>>>> suggest making the compression optional via configuration so that anyone
>>>> with smaller channels don’t end up using CPU for not much gain.
>>>>
>>>>
>>>> Thanks,
>>>> Hari
>>>>
>>>> On Monday, June 9, 2014 at 3:56 PM, Abraham Fine wrote:
>>>>
>>>> Hello-
>>>>
>>>> We are using Flume 1.4 with File Channel configured to use a very
>>>> large capacity. We keep the checkpoint and backup checkpoint on
>>>> separate disks.
>>>>
>>>> Normally the file channel is mostly empty (<<1% of capacity). For the
>>>> checkpoint the disk I/O seems to be very reasonable due to the usage
>>>> of a MappedByteBuffer.
>>>>
>>>> On the other hand, the backup checkpoint seems to be written to disk
>>>> in its entirety over and over again, resulting in very high disk
>>>> utilization.
>>>>
>>>> I noticed that, because the checkpoint file is mostly empty, it is
>>>> very compressible. I was able to GZIP our checkpoint from 381M to
>>>> 386K. I was wondering if it would be possible to always compress the
>>>> backup checkpoint before writing it to disk.
>>>>
>>>> I would be happy to work on a patch to implement this functionality if
>>>> there is interest.
>>>>
>>>> Thanks in Advance,
>>>>
>>>> --
>>>> Abraham Fine | Software Engineer
>>>> (516) 567-2535
>>>> BrightRoll, Inc. | Smart Video Advertising | www.brightroll.com
>>>>
>>>>
>>>>
>>>
>>
>

Mime
View raw message