I saw you popped into this issue with PHPRedis here:
phpredis/phpredis#70

It might completely reside with them but thought I would post here in case you had found a solution outside of PHPRedis to handle this with Cm_Cache_Backend_Redis.

The only new thing I saw of note in that thread was within the past few weeks:

"I encountered this same error message. Using the tip from @redzarf - I did some research and found that some of the strings we were trying to store are indeed more than 64KB (65,536 Characters).

As a quick solution I started gzip'ing data before storing it in redis. Havn't seen the "read error on connection" error since."

Here are some of my dump(s) when this hits:

Error:
read error on connection

Trace:
#0 /app/code/community/Cm/Cache/Backend/Redis.php(128): Credis_Client->__call('hGet', Array)
#1 /app/code/community/Cm/Cache/Backend/Redis.php(128): Credis_Client->hGet('zc:k:139_TRANSL...', 'd')
#2 /lib/Zend/Cache/Core.php(303): Cm_Cache_Backend_Redis->load('139_TRANSLATE_E...', false)
#3 /app/code/core/Mage/Core/Model/Cache.php(351): Zend_Cache_Core->load('TRANSLATE_EN_US...')
#4 /app/code/core/Mage/Core/Model/App.php(1126): Mage_Core_Model_Cache->load('translate_en_US...')
#5 /app/code/core/Mage/Core/Model/Translate.php(521): Mage_Core_Model_App->loadCache('translate_en_US...')
#6 /app/code/core/Mage/Core/Model/Translate.php(121): Mage_Core_Model_Translate->_loadCache()
#7 /app/code/core/Mage/Core/Model/App/Area.php(146): Mage_Core_Model_Translate->init('frontend')
#8 /app/code/core/Mage/Core/Model/App/Area.php(121): Mage_Core_Model_App_Area->_initTranslate()
#9 /app/code/core/Mage/Core/Model/App/Area.php(93): Mage_Core_Model_App_Area->_loadPart('translate')
#10 /app/code/core/Mage/Core/Model/App.php(768): Mage_Core_Model_App_Area->load()
#11 /app/code/core/Mage/Core/Controller/Varien/Action.php(493): Mage_Core_Model_App->loadArea('frontend')
#12 /app/code/core/Mage/Core/Controller/Front/Action.php(59): Mage_Core_Controller_Varien_Action->preDispatch()
#13 /app/code/core/Mage/Core/Controller/Varien/Action.php(409): Mage_Core_Controller_Front_Action->preDispatch()
#14 /app/code/core/Mage/Core/Controller/Varien/Router/Standard.php(250): Mage_Core_Controller_Varien_Action->dispatch('view')
#15 /app/code/core/Mage/Core/Controller/Varien/Front.php(176): Mage_Core_Controller_Varien_Router_Standard->match(Object(Mage_Core_Controller_Request_Http))
#16 /app/code/core/Mage/Core/Model/App.php(349): Mage_Core_Controller_Varien_Front->dispatch()
#17 /app/Mage.php(640): Mage_Core_Model_App->run(Array)
#18 /index.php(83): Mage::run('', 'store')
#19 {main}

Error:
read error on connection

Trace:
#0 /app/code/community/Cm/Cache/Backend/Redis.php(128): Credis_Client->__call('hGet', Array)
#1 /app/code/community/Cm/Cache/Backend/Redis.php(128): Credis_Client->hGet('zc:k:139_DB_PDO...', 'd')
#2 /lib/Zend/Cache/Core.php(303): Cm_Cache_Backend_Redis->load('139_DB_PDO_MYSQ...', false)
#3 /lib/Varien/Db/Adapter/Pdo/Mysql.php(1442): Zend_Cache_Core->load('DB_PDO_MYSQL_DD...')
#4 /lib/Varien/Db/Adapter/Pdo/Mysql.php(1564): Varien_Db_Adapter_Pdo_Mysql->loadDdlCache('eav_attribute', 1)
#5 /app/code/core/Mage/Catalog/Model/Resource/Product/Attribute/Collection.php(55): Varien_Db_Adapter_Pdo_Mysql->describeTable('eav_attribute')
#6 /app/code/core/Mage/Core/Model/Resource/Db/Collection/Abstract.php(135): Mage_Catalog_Model_Resource_Product_Attribute_Collection->_initSelect()
#7 /app/code/core/Mage/Core/Model/Config.php(1350): Mage_Core_Model_Resource_Db_Collection_Abstract->__construct(Array)
#8 /app/code/core/Mage/Core/Model/Config.php(1386): Mage_Core_Model_Config->getModelInstance('catalog_resourc...', Array)
#9 /app/Mage.php(460): Mage_Core_Model_Config->getResourceModelInstance('catalog/product...', Array)
#10 /app/code/core/Mage/Catalog/Model/Layer.php(226): Mage::getResourceModel('catalog/product...')
#11 /app/code/core/Mage/Catalog/Block/Layer/View.php(163): Mage_Catalog_Model_Layer->getFilterableAttributes()
#12 /app/code/local/Lp/Catalog/Block/Layer/View.php(121): Mage_Catalog_Block_Layer_View->_getFilterableAttributes()
#13 /app/code/core/Mage/Core/Block/Abstract.php(238): Lp_Catalog_Block_Layer_View->_prepareLayout()
#14 /app/code/core/Mage/Core/Model/Layout.php(430): Mage_Core_Block_Abstract->setLayout(Object(Mage_Core_Model_Layout))
#15 /app/code/core/Mage/Core/Model/Layout.php(446): Mage_Core_Model_Layout->createBlock('catalog/layer_v...', 'catalog.leftnav')
#16 /app/code/core/Mage/Core/Model/Layout.php(238): Mage_Core_Model_Layout->addBlock('catalog/layer_v...', 'catalog.leftnav')
#17 /app/code/core/Mage/Core/Model/Layout.php(204): Mage_Core_Model_Layout->_generateBlock(Object(Mage_Core_Model_Layout_Element), Object(Mage_Core_Model_Layout_Element))
#18 /app/code/core/Mage/Core/Model/Layout.php(209): Mage_Core_Model_Layout->generateBlocks(Object(Mage_Core_Model_Layout_Element))
#19 /app/code/core/Mage/Core/Controller/Varien/Action.php(345): Mage_Core_Model_Layout->generateBlocks()
#20 /app/code/core/Mage/Catalog/controllers/CategoryController.php(150): Mage_Core_Controller_Varien_Action->generateLayoutBlocks()
#21 /app/code/core/Mage/Core/Controller/Varien/Action.php(420): Mage_Catalog_CategoryController->viewAction()
#22 /app/code/core/Mage/Core/Controller/Varien/Router/Standard.php(250): Mage_Core_Controller_Varien_Action->dispatch('view')
#23 /app/code/core/Mage/Core/Controller/Varien/Front.php(176): Mage_Core_Controller_Varien_Router_Standard->match(Object(Mage_Core_Controller_Request_Http))
#24 /app/code/core/Mage/Core/Model/App.php(349): Mage_Core_Controller_Varien_Front->dispatch()
#25 /app/Mage.php(640): Mage_Core_Model_App->run(Array)
#26 /index.php(83): Mage::run('', 'store')
#27 {main}