Many VLF and always on availability group performance

  • Hello. In our SQL Server i see HADR_LOGCAPTURE_WAIT as one of the top waits in system. As mentioned at msdn, HADR_LOGCAPTURE_WAIT is Waiting for log records to become available. Can occur either when waiting for new log records to be generated by connections or for I/O completion when reading log not in the cache. There is not much information about this wait in the internet. But while digging it, i also find, that there are a lot of VLF files in our database(about 600-1000) transaction logs. So the question is - if there is any dependence between number of VLF files and high waits? Or this high wait times are ok?

    Thanks.

  • i would certainly start by resolving the VLF issue first, in fact when the VLF count gets over a 1000 sql server starts to alert in the error log that the database has x number of VLFs

    -----------------------------------------------------------------------------------------------------------

    "Ya can't make an omelette without breaking just a few eggs" 😉

Viewing 2 posts - 1 through 2 (of 2 total)

You must be logged in to reply to this topic. Login to reply