I had an index fail with NoClassDefFoundError - this then meant that all Jira functionality was lost (couldn't search for or create issues, admin tools all messed up)
Stopping Jira, deleting indexes and removing plugins from installedplugins and then re-starting overcame and I gradually added plugins re-indexing as I went and re-index went fine at each stage
I upgraded Groovy Runner from 2.1 Beta 7 to 2.1 Beta 8 and I didn't get the NoClassDefFoundError but the re-index did fail, this time with Too Many Open Files
I upped ullimit to 4096 and it now re-indexes successfully
I don't have that many Groovy Files (1 scripted field is a file and a few workflow transitions have groovy files) and this is a test system with relatively low volume of issues so I'm reticent to move it to production until I overcome the issue.
Any ideas why it might be keeping too many files open (or indeed why the first time failed with NoClassDefFoundError and not the 2nd when I didn't change any scripted files or script transitions/fields)?