Last week we had a issue with our exchange environment where we were unable to send and receive email both internally and externally.
When I ran this command
Get-MailboxDatabase -Status | Select-Object Name,@{N="DatabaseSize GB";E={"$([math]::round($_.DatabaseSize.Tobytes() /1Gb, 2)) GB"}},AvailableNewMailboxSpace | Sort-Object Name | fl
It returned a value that looked like this:
Name : Mailbox Database ######
DatabaseSize GB : 541 GB
AvailableNewMailboxSpace : 84 MB (84000000 bytes)
I checked the drive that exchange resides on and found it to have plenty of free space (365GB).
From all of the research I had found everyone said that exchange will just continue to grow and there is not a (soft limit) in place for Exchange 2013. I found one anyway and gave it a try
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSExchangeIS\<Server Name>\Private-<database GUID>
I then added a DWORD key for Database Size Limit in GB setting the value to 700.
After restarting all exchange services I ran the command again and it didn't show anything really different other than the MB remaining continued to dwindle.
So, I figured this must be since the actual "size" didn't change but now it could grow. Well, when we hit 0MB remaining the DB did grow slightly and the countdown begain again somewhere in the upper double digits.
This continued throughout the day. I could get mail flowing again with a restart of services or rebuilding the transport QUE folder but it wouldn't sustain. Eventually, out of ideas I found some mailboxes that were old and could be purged out and I recovered about 20GB of "Available New Mailbox Space". Then with a restart of the exchange services we became stable again.
It "sounds like" I hit a storage limit of some kind. I do not see any quota's set on the database itself for "prohibiting send / rec" at any type of storage level. IS there somewhere that a database max size is set (other than the registry I tried and since have removed).
I was supposed to onboard another 20 mailboxes into our environment this week and I'm thinking this issue is going to prevent that unless I can find away to get us past 541GB.
Get-Mailbox -ResultSize Unlimited | Get-MailboxFolderStatistic