Subject gbak crashes FB
Author anchovies

We have a db about 100GB in size with 5 tables about 50million rows each running FB 2.1.3.

While trying to do gbak backup it exits with the error below:
gbak: ERROR:connection lost to database
gbak: ERROR: gds_$receive failed
gbak:Exiting before completion due to errors
gbak: ERROR:Error writing data to the connection.

The steps we tried and observations as per below:
1) gbak using localhost:[path to db] - same error as above
2) Then tried gbak using local connection [path to db] without localhost - same error as above
3) All RAM are used up when running gbak - 8Gb
4) Always exits with error on the largest table. Did not have the chance to backup other tables yet during gbak.
5) When error happens, FB service will shutdown itself.

DB header as below:
Database header page information:
Flags 0
Checksum 12345
Generation 54653778
Page size 16384
ODS version 11.1
Oldest transaction 40079365
Oldest active 54646607
Oldest snapshot 54646607
Next transaction 54652533
Bumped transaction 1
Sequence number 0
Next attachment ID 3776954
Implementation ID 26
Shadow count 0
Page buffers 0
Next header page 0
Database dialect 3
Attributes force write

Variable header data:
Sweep interval: 0

We have turned off auto-sweep as our application is also having similar errors as "Error writing data to the connection".
Turning off auto-sweep did solved abit this "Error writing data..." issue, but does crop up now and then.

Since now there seems no way for us to do backup, any suggestions what we shd do?
Application can't be taken offline =(

Much Thanks,