Engineering and technology notes

Mechanics of Flite – Disabling binlog_checksum for MySQL 5.5/5.6 master-master replication

Jovan Stosic August 21, 2018

Disabling Binlog_checksum for MySQL 5.5/5.6 Master-master Replication

Replicating from a newer major version to an older major version in MySQL (for example a 5.6 master and a 5.5 replica) is generally not recommended, but when upgrading a master-master replication topology it’s hard to avoid this scenario entirely. We ended up in this situation last week when upgrading the passive master of an active-passive master-master pair from 5.5 to 5.6. The primary replication flow was going from the active master (5.5) to the passive master (5.6) with no errors, but pt-heartbeat was running on the passive master, which led to a replication failure with this error on the active master:

Last_IO_Error: Got fatal error 1236 from master when reading data from binary log: ‘Slave can not handle replication events with the checksum that master is configured to log; the first event ‘bin-log.002648’ at 4, the last event read from ‘/var/lib/mysqllogs/bin-log.002648’ at 120, the last byte read from ‘/var/lib/mysqllogs/bin-log.002648’ at 120.’

Why did this happen? Starting in MySQL 5.6.6, the new binlog_checksum option defaults to CRC32. Since that option did not exist in MySQL 5.5, the replica can’t handle the checksums coming from the master. Therefore I recommend setting binlog_checksum=NONE in my.cnf as part of the upgrade process for a master-master setup to avoid this error.

My fix was to run this on the passive master:

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set global binlog_checksum='NONE';

Then I added this to my.cnf so it would survive a restart:

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binlog_checksum=NONE

After that change was made I examined the binary log to confirm that it did not include anything other than pt-heartbeat activity, and then executed CHANGE MASTER on the active master to skip the checksummed events.

Once the other master is upgraded I can go back and consider changing binlog_checksum to CRC32.

Source: Mechanics of Flite – Disabling binlog_checksum for MySQL 5.5/5.6 master-master replication

Samsung LE-32M61B – 32″ LCD TV – widescreen – 720p – HDTV monitor

Jovan Stosic August 19, 2018

Product Description Samsung LE-32M61B – 32″ LCD TVProduct Type LCD TVDiagonal Size 32″ – widescreenDimensions (WxDxH) 80.4 cm x 25 cm x 62.3 cmWeight 19.2 kgColour BlackDigital Television Certification HDTV monitorResolution 1366 x 768Display Format 720pVideo Interface Component, composite, HDMI, S-Video, SCARTHDMI Ports Qty 1 port(s)PC Interface VGA (HD-15)Technology TFT active matrixImage Aspect Ratio 16:9Analogue TV Tuner PAL, SECAMFeatures Auto noise reduction, DNIe (Digital Natural Image engine)Sound Output Mode StereoSpeaker System 2 speakersSound Effects SRS TruSurround XTStereo Reception System NICAM, A2GENERALProduct Type 32″ LCD TVDigital Television Certification HDTV monitorVideo Interface Component, composite, HDMI, S-Video, SCARTHDMI Ports Qty 1 port(s)PC Interface VGA (HD-15)Width 80.4 cmDepth 25 cmHeight 62.3 cmWeight 19.2 kgEnclosure Colour BlackDISPLAYDiagonal Size 32″ – widescreenTechnology TFT active matrixResolution 1366 x 768Display Format 720pImage Aspect Ratio 16:9Dynamic Contrast Ratio 5000:1Brightness 500 cd/m2Viewing Angle 178 degreesViewing Angle (Vertical) 178 degreesColour Temperature Control YesFeatures Auto noise reduction, DNIe (Digital Natural Image engine)TV TUNERAnalogue TV Tuner PAL, SECAMReception System PAL, SECAM-I, SECAM-D, SECAM-B, SECAM-K, SECAM-G, SECAM-LStereo Reception System NICAM, A2VIDEO FEATURESHDTV Ready Built-inTeletext YesTeletext Memory 1000 pagesAUDIO SYSTEMSound Output Mode StereoSurround Mode Built-inSound Effects SRS TruSurround XTEqualiser Yes (5-band)Speakers Included 2 speakersOutput Power / Total 20 WattSpeaker(s) 2 x right/left channel speaker – built-in – 10 WattCONNECTIONSConnector Type 1 x VGA input ( 15 PIN HD D-Sub (HD-15) )1 x component video input ( RCA phono x 3 )1 x HDMI1 x headphones1 x composite video input ( RCA phono )1 x S-Video input ( 4 PIN mini-DIN )2 x SCART ( 21 PIN SCART )1 x composite video output ( RCA phono )1 x antennaMISCELLANEOUSIncluded Accessories LCD TV standPOWERPower Consumption Stand by / Sleep 3 WattPower Consumption Operational 170 WattDIMENSIONS & WEIGHT DETAILSDimensions & Weight Details TV set – 80.4 cm x 11.3 cm x 56.4 cmTV set with stand – 80.4 cm x 25 cm x 62.3 cm x 19.2 kg
http://www.backoffice.be/prod_uk/Samsung/le-32m61b_samsung_le-32m61b_32_dquote_lcd_tv_widescreen_720p.asp