Database backup using Nbackup is getting slow when directed to NAS over SMB protocol ------------------------------------------------------------------------------------
Key: CORE-4913 URL: http://tracker.firebirdsql.org/browse/CORE-4913 Project: Firebird Core Issue Type: Improvement Components: NBACKUP Affects Versions: 3.0 Beta 2, 2.5.4, 2.5.3 Update 1, 2.1.7, 3.0 Beta 1, 2.5.3, 2.1.6, 3.0 Alpha 2, 3.0 Alpha 1, 2.5.2 Update 1, 2.1.5 Update 1, 2.5.2, 2.5.1, 2.5.0, 3.0 RC 1, 2.5.5, 4.0 Initial, 3.0.0 Environment: Windows Server 2003 32 bit, 1Gbit ethernet, NAS QNAP ts-439 RAID 5 Reporter: Jan Hejda Priority: Minor After a few years of running well, the backup of 60GB database suddenly slowed down during one month from 2.5 hours to 24 hours. It was slow only for that Linux based NAS, the speed for Windows shared directories was about 2.5 hours. After below described change I achieved the speed allowing the same backup to be done within 40 minutes. In the function void nbackup::create_backup() in the function call CreateFile I changed the flag GENERIC_WRITE to GENERIC_READ | GENERIC_WRITE. The reason for the change is described in MSDN (https://msdn.microsoft.com/en-us/library/windows/desktop/aa363858(v=vs.85).aspx): When an application creates a file across a network, it is better to use GENERIC_READ | GENERIC_WRITE for dwDesiredAccess than to use GENERIC_WRITE alone. The resulting code is faster, because the redirector can use the cache manager and send fewer SMBs with more data. This combination also avoids an issue where writing to a file across a network can occasionally return ERROR_ACCESS_DENIED. -- This message is automatically generated by JIRA. - If you think it was sent incorrectly contact one of the administrators: http://tracker.firebirdsql.org/secure/Administrators.jspa - For more information on JIRA, see: http://www.atlassian.com/software/jira ------------------------------------------------------------------------------ Firebird-Devel mailing list, web interface at https://lists.sourceforge.net/lists/listinfo/firebird-devel