Every 30 minutes, almost by clockwork, a get the following error on my Windows 2008 R2 servers:
Log Name: System
Source: MSiSCSI
Event ID: 113
Level: Warning
Description:
iSCSI discovery via SendTargets failed with error code 0xefff0003 to target portal *10.2.62.3 0003260 B06BDRV\L4SC&PCI_163A14E4&SUBSYS_045F1028&REV_20\5&cabe3b7&0&30050200_0
I have 12 identically built servers connected to this iSCSI network and they are all seeing this issue. I've updated drivers and firmware levels without any change. Any other obvious things I should try before engaging my network team and the vendors.
If you aren't actually getting disconnected from the target, or if you can immediately reconnect, then it's most likely a temporary issue with the network connectivity.
See Microsoft KB article 976072: Event ID 1, event ID 5, event ID 70, or event ID 113 may be logged in the System log on a computer that uses the iSCSI Software Initiator to connect to an iSCSI target device.
Looks to me like it's time to take it up with the network team, though since it happens on all the iSCSI initiators, it's probably a problem with or at the target.
The KB article also lists other possible causes, but they seem very unlikely. You may wish to check for them anyway.