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Enterprise 1.14.1.0, nginx, php-fpm, solr, redis (2 instances - one for fpc, and one for everything else)

We're completely at our wit's end - we have tweaked every configuration setting that seems plausible... and the issue persists every single day. Any ideas would be greatly appreciated.

Our site experiences redis locking up and dumping errors like this for several minutes, then things clear up and resume back to normal.

 a:4:{i:0;s:24:"read error on connection";i:1;s:1196:"#0 /var/www/magento/lib/Credis/Client.php(440): Credis_Client->__call('select', Array)
#1 /var/www/magento/lib/Cm/Cache/Backend/Redis.php(117): Credis_Client->select(0)
#2 /var/www/magento/lib/Zend/Cache.php(153): Cm_Cache_Backend_Redis->__construct(Array)
#3 /var/www/magento/lib/Zend/Cache.php(94): Zend_Cache::_makeBackend('Cm_Cache_Backen...', Array, true, true)
#4 /var/www/magento/app/code/local/Extendware/EWCacheBackend/Model/Override/Mage/Core/Cache.php(25): Zend_Cache::factory()
#5 /var/www/magento/app/code/core/Mage/Core/Model/Config.php(1348): ExtendwareInternal_EWCacheBackend_Model_Override_Mage_Core_Cache->__construct(Array)
#6 /var/www/magento/app/Mage.php(463): Mage_Core_Model_Config->getModelInstance('core/cache', Array)
#7 /var/www/magento/app/code/core/Mage/Core/Model/App.php(401): Mage::getModel('core/cache', Array)
#8 /var/www/magento/app/code/core/Mage/Core/Model/App.php(295): Mage_Core_Model_App->_initCache(Array)
#9 /var/www/magento/app/code/core/Mage/Core/Model/App.php(337): Mage_Core_Model_App->baseInit(Array)
#10 /var/www/magento/app/Mage.php(684): Mage_Core_Model_App->run(Array)
#11 /var/www/magento/index.php(87): Mage::run('default', 'store')
#12 {main}";s:3:"url";s:48:"/";s:11:"script_name";s:10:"/index.php";}
  • Magento Support has confirmed proper configuration from the Magento side (they logged in, investigated, ran tests, and claim it's "server issue" not a Magento issue)
  • Our host (Peer1) has some Magento specialists who have spent many hours working with us to diagnose the problem... and can't yet find any specific issues with resourcing of RAM, redis config, etc, etc.
  • Our RAM has been doubled to 64 GB, and we are currently sitting with about 20GB of RAM sitting free.
  • PHP, PHP-FPM are consuming a LOT of CPU
  • This is all on the web server, the db server is separate and running fine

Here's a snapshot of Top during normal operations (when errors are not occuring)

top - 12:13:47 up 2 days, 16:05,  2 users,  load average: 6.51, 7.33, 7.26
Tasks: 639 total,  13 running, 625 sleeping,   0 stopped,   1 zombie
Cpu(s): 47.7%us,  1.1%sy,  0.0%ni, 50.9%id,  0.0%wa,  0.0%hi,  0.2%si,  0.0%st
Mem:  65937660k total, 41186844k used, 24750816k free,   551968k buffers
Swap:  8388604k total,        0k used,  8388604k free, 13040128k cached

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND                                                                          
29720 nginx     20   0 1927m 553m  12m R 99.6  0.9 615:37.52 php                                                                              
 8638 nginx     20   0 1532m 146m 9236 R 98.3  0.2   4:01.43 php-fpm                                                                          
 8618 nginx     20   0 1582m 195m 8268 R 96.3  0.3   4:06.96 php-fpm                                                                          
 8664 nginx     20   0 1521m 144m 6932 S 96.0  0.2   4:12.06 php-fpm                                                                          
 8699 nginx     20   0 1582m 196m 9508 R 94.0  0.3   3:33.90 php-fpm                                                                          
 8740 nginx     20   0 1581m 194m 8188 R 94.0  0.3   4:05.63 php-fpm                                                                          
 8735 nginx     20   0 1583m 196m 9204 R 90.4  0.3   4:27.89 php-fpm                                                                          
 8634 nginx     20   0 1582m 195m 8080 R 81.4  0.3   4:07.25 php-fpm                                                                          
 8727 nginx     20   0 1529m 141m 9076 S 73.8  0.2   4:54.04 php-fpm                                                                          
 8597 nginx     20   0 1529m 143m 8020 S 62.6  0.2   3:56.57 php-fpm                                                                          
 8743 nginx     20   0 1518m 132m 9204 R 51.0  0.2   4:10.01 php-fpm                                                                          
 8601 nginx     20   0 1517m 132m 9284 S 48.7  0.2   4:04.32 php-fpm                                                                          
 8611 nginx     20   0 1530m 143m 8104 S 38.7  0.2   4:12.82 php-fpm                                                                          
 8614 nginx     20   0 1511m 124m 8216 R 28.1  0.2   3:26.96 php-fpm                                                                          
 8714 nginx     20   0 1532m 145m 8260 S 27.5  0.2   4:15.64 php-fpm                                                                          
 8684 nginx     20   0 1528m 142m 8232 R 22.8  0.2   4:01.39 php-fpm                                                                          
 8700 nginx     20   0 1519m 142m 5216 R 22.8  0.2   4:44.06 php-fpm                                                                          
 8691 nginx     20   0 1532m 146m 8208 R 19.5  0.2   4:32.76 php-fpm                                                                          
 8622 nginx     20   0 1533m 146m 8216 S 16.2  0.2   4:57.07 php-fpm                                                                          
 9134 redis     20   0  880m 175m  888 S  4.6  0.3  36:39.15 redis-server                                                                     
 9112 redis     20   0 1192m 354m  880 S  2.6  0.6  57:50.85 redis-server                                                                     
 8566 nginx     20   0 93340 5084 1784 S  1.0  0.0   0:02.75 nginx   

Here's our Magento Config for Redis:

<!-- redis cache -->
<cache>
    <backend>Cm_Cache_Backend_Redis</backend>
    <backend_options>
        <server>127.0.0.1</server>
        <port>6379</port>
        <database>0</database>
        <password></password>
        <force_standalone>0</force_standalone> 
        <connect_retries>1</connect_retries>
        <automatic_cleaning_factor>0</automatic_cleaning_factor>
        <compress_data>1</compress_data>
        <compress_tags>1</compress_tags>
        <compress_threshold>20480</compress_threshold>
        <compression_lib>gzip</compression_lib>
        <persistent></persistent>
        <read_timeout>10</read_timeout>
    </backend_options>
</cache>
<!-- redis full page cache -->
<full_page_cache>
    <backend>Cm_Cache_Backend_Redis</backend>
    <backend_options>
        <server>127.0.0.1</server>
        <port>6380</port>
        <database>1</database>
        <password></password>
        <force_standalone>0</force_standalone>
        <connect_retries>1</connect_retries>
        <automatic_cleaning_factor>0</automatic_cleaning_factor>
        <compress_data>0</compress_data>
        <lifetimelimit>57600</lifetimelimit>
        <persistent></persistent>
        <read_timeout>10</read_timeout>
    </backend_options>
</full_page_cache>

I've reviewed the Redis slow log and found quite a few (seemingly) massive saves that are taking a while... note that ONLY the full-page-cache instance has any entries in the slow log. Are these normal? These are the full page cache instance. Here's two examples of the 250 entries in the slow log:

 7) 1) (integer) 356
    2) (integer) 1429287105
    3) (integer) 40685
    4)  1) "DEL"
        2) "zc:k:e84_REQEST_91D0FF548C77B6F58148AF6A7F586C58"
        3) "zc:k:e84_REQEST_8212780F50033B79092F556EE14C1E6E"
        4) "zc:k:e84_REQEST_86DCFE6E580707552F38B507272FD2FA"
        5) "zc:k:e84_REQEST_FE69215CAA18AA2D33DE6DE2E31F7491"
        6) "zc:k:e84_1ED6001E13E4EEA9AB6E19EEC6742A89_1_3_745"
        7) "zc:k:e84_REQEST_45ACA3435B0016847D4B060C6436B366"
        8) "zc:k:e84_REQEST_985ED12A38AFD74402B159AF8B1B5741"
        9) "zc:k:e84_REQEST_11022B655050F20ED54B4AE51EF12CE6"
       10) "zc:k:e84_REQEST_26CA3F7EA8612325E845B3B236E0CCFE"
       11) "zc:k:e84_REQEST_646FBF4016B630643F3D06C2162721F6_METADATA"
       12) "zc:k:e84_REQEST_29C5D2EC342997382A7DB7DF7DDD2F6D"
       13) "zc:k:e84_REQEST_F8A6D1AF029997A51F3D1A4E2F3CB725"
       14) "zc:k:e84_REQEST_8DBB0D20DDFC426B089F52432757C47E"
       15) "zc:k:e84_REQEST_5EA7B23B0B309045EB6A81EF4B9E6A66_METADATA"
       16) "zc:k:e84_REQEST_EA531324268EF209504816504B114FAC"
       17) "zc:k:e84_REQEST_7C659A3F9178A62AED9B0499AEED0130"
       18) "zc:k:e84_REQEST_6807CA64C0FF1C29B4069BF3B472252B"
       19) "zc:k:e84_8C636CBFA6DB338DD11F600771E54FAC_1_3_43_288"
       20) "zc:k:e84_REQEST_E062EAC26446FACE3025FC6AE1E632A9"
       21) "zc:k:e84_7D5DE581F27790730C0E000F9D69F2E3_1_3_53_53"
       22) "zc:k:e84_REQEST_C4F854BA432A2884E49A1BA245D756A5"
       23) "zc:k:e84_REQEST_922C03E387E66DF9EBBCE0186BD67C3C"
       24) "zc:k:e84_REQEST_503B90ED3CBE43438A0C740A68B1E576_METADATA"
       25) "zc:k:e84_REQEST_7B9B9FAAE5FA78DB6934DC0658BC5D83"
       26) "zc:k:e84_REQEST_E8FE8236DDA57C9830B7843623310E86"
       27) "zc:k:e84_REQEST_5826188B159CBCD0E7E9BFBE3BB1D599"
       28) "zc:k:e84_REQEST_37F7CBE45FEF49E4D7F38ECE4B760996"
       29) "zc:k:e84_REQEST_AACD280C3AB5E27760E80A4D1888AD1F"
       30) "zc:k:e84_REQEST_47CE15DD5D5391B1413F5ECF150533DB"
       31) "zc:k:e84_REQEST_E261C23C996BC8D45111F2A23DDED93A"
       32) "... (1633 more arguments)"
10) 1) (integer) 353
    2) (integer) 1429285945
    3) (integer) 37193
    4)  1) "DEL"
        2) "zc:k:e84_REQEST_92BAB7E07D28861B459120B0CDCF0AD7"
        3) "zc:k:e84_REQEST_32FC6F43EABA88A2E665630C189A751C"
        4) "zc:k:e84_REQEST_55E596F3198540E5E249CB2A4C2690D1"
        5) "zc:k:e84_REQEST_B5F8BD16ED9D77245DC1FE0201FE1B1B"
        6) "zc:k:e84_REQEST_CBBFFAEAABE47237EF465B6D00BE39F7"
        7) "zc:k:e84_REQEST_D5BD191B4E0389F1C60271CCD33163BE"
        8) "zc:k:e84_1ED6001E13E4EEA9AB6E19EEC6742A89_1_3_745"
        9) "zc:k:e84_REQEST_E498601DC7D6D799B358A8B5A86FC783"
       10) "zc:k:e84_REQEST_6A6D07696354D06F1414F3F7A5A3967A"
       11) "zc:k:e84_REQEST_EB6E820EA5D8598C008BA4A94C2AC904"
       12) "zc:k:e84_REQEST_EEACD0C782C80044325B4E04D32E0F34"
       13) "zc:k:e84_REQEST_8CD8334B055C58AD92208DB9BE0F9D1D_METADATA"
       14) "zc:k:e84_REQEST_70EFDB6D70BE88D367B0C48629E561FE"
       15) "zc:k:e84_REQEST_B9FF6FA7A3CFE8B1F1521A73DF71D308"
       16) "zc:k:e84_REQEST_14310D5749525D4828E6B6D2F090A366"
       17) "zc:k:e84_REQEST_0CE5E095669A57D17FD780A3BA72A84F_METADATA"
       18) "zc:k:e84_REQEST_28B2C39A828640D0B1A49E77A56F6A09"
       19) "zc:k:e84_REQEST_17EF76BC89E5EE5DDDB0D752514BBCC4"
       20) "zc:k:e84_REQEST_76B91839CA4F29C45E4628C67A8FEFDE"
       21) "zc:k:e84_REQEST_F4D7B7D455BF29C8A281D6CC387A86D9"
       22) "zc:k:e84_7878AC51A7ECCF1F57E2E74B6FF3CD20_1_3_10_750"
       23) "zc:k:e84_REQEST_90B19F2BBC6EA90C7AC1F91242C316A8"
       24) "zc:k:e84_8C636CBFA6DB338DD11F600771E54FAC_1_3_43_288"
       25) "zc:k:e84_REQEST_0C95AC5E87D3F74F62A1FBE5B822A9B2"
       26) "zc:k:e84_7D5DE581F27790730C0E000F9D69F2E3_1_3_53_53"
       27) "zc:k:e84_REQEST_3B852462504D3226F5F73D387C0C250F"
       28) "zc:k:e84_REQEST_5A5403A3603FD208332F9CBD631C8B4B_METADATA"
       29) "zc:k:e84_REQEST_B8152798A9D1F3C4C45C876FC9F2942A"
       30) "zc:k:e84_REQEST_2E12C5B2DD8B55BB5D4343DF9241EA29"
       31) "zc:k:e84_REQEST_B241A180FBB7E511A74C2129667C2BAD"
       32) "... (3272 more arguments)"
  • 1
    Did you have a look at github.com/colinmollenhour/Cm_Cache_Backend_Redis/issues/18 – David Manners Apr 18 '15 at 15:36
  • first of all - upgrade redis and phpredis, then change compression lib to lzf or snappy, then PHP-FPM are consuming a LOT of CPU because of a bad code, or you have some evil loops running somewhere, run profiler or database monitoring, and FYI - at PEER1 there are no specialists, unfortunately, all they can do to force customers to buy a huge expensive servers in the hope that a huge amount of memory will help cope with the problems ... – user2857 Apr 20 '15 at 18:42
  • Could I see your /etc/php-fpm.d/www.conf ? – DarkMukke Jan 22 '16 at 11:49
  • That is why while running in production, people usually have more than 1 server. Usually 1 WEB with a lot of CPUs, 1 DB with a lot of RAM and 1 CACHE (redis, varnish...) with a lot of CPUs and a quite lot of RAM. – Toan Nguyen Apr 20 '16 at 1:56
  • Did you try to raise <connect_retries>1</connect_retries> to a higher number like 3? – Anna Völkl Feb 3 '17 at 23:43
1

You might try checking for network connection limits. We've seen that happen before where something opens a TON of connections to Redis, and stops further connections, then goes away on its own. The error messages are deceptive because they won't flat out say that and it takes some poking around to actually figure that out.

I.e. Redis can only have so many open connections, as may a given service on your particular setup, so if you hit that it won't appear in any Magento/Redis logs directly.

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