Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
Greetings. I am administrator of an Alfresco DMS running on an dedicated ubuntu server and is backedup to a streamer via a simple cron job. Unfortunately my predecessor (who set up this backup process) did not know that streaming a backup while the DMS is running causes mysql database inconsistencies preventing the DMS to boot after recovery. boo-hoo Running a proper cold back requires approx 2h while the DMS is shutdown. Thats just to long. One way would be to set up a slave-read-only-dms-site with mysql replication which can be shutdown for backup anytime while the master system is still running. In my opinion this is a waste of ressources because the slave site got to be up all the time, only building indices out of the replicated mysql data. In the course of an Upgrade to a newer version of the DMS I plan to implement a new backup process using DRBD involving a well equipped Master-DMS-Site and a MiniDRBD-Site for backup on another machine. 1. I have two virtual machines on two separate physical machines. VM1= MasterSite VM2=MiniDRBD 2. VM1 is running Ubuntu Server, RDBD, iptables, sshd, mysqld, oOffice-headless and tomcat. 3. Residents of VM2 are Ubuntu Server, RDBD, sshd and iptables 4. VM1 and VM2 use a virtual HardDisk /dev/sdb each residing on the corresponding physical machine 5. RDBD repilicates "VM1/dev/sdb0" to "VM2/dev/sdb0" via /dev/drdb0 6. VM1 stores all DMS relevant data including mysql database and indices on /dev/drdb0 To stream a cold BackUp with minimal DownTime I intend to use the following procedure: 1. crontab a shell script on VM1 which => stops DMS closing the database properly => RDBD replicates the closed state of the database to VM2/dev/sdb0 via /dev/drbd0 => stops replication via "drbdadm disconnect MyFS" => starts the DMS again => waits for 2.5h and starts replication via "drbdadm connect MyFS" => exits 2. Five Minutes after 1. started I crontab a shell script on VM2 which => mounts VM2/dev/drdb0 to e.g. /media/drdb0 => streams all files to tape via "tar cvf - /media/drdb0/* | dd of=/dev/str0/n block-size=4096" => umounts /media/drdb0 => exits (I think that:) Streaming a BackUp that way reduces the downtime of the Master (VM1/alfresco) to about 10 seconds instead of 2 hours. Additionally it (i hope) nearly halves required CPU time and RAM usage in comparison to the mysql-replication approach that is recommended by the Alfresco-DMS vendor. (:but I may be wrong) Some general questions: Q1. I wonder if DRDB will autosync all changes made on the master during the "disconnect" to the slave after a "drbdadm connect MyFS" (in script 1. on VM1). Q2. How long will it take drbd to replicate the closed state of a 150mb database to VM2 so I can stop replication? (1GB/s LAN) Q3. What do you think would be the minimum specs for my miniRDBD machine (VM2). (128RAM,1core,256swap?) Q4. Do you have any suggestions how to use drbd a smarter way for my backup purposes. Q5. <Non drbd question> What is the best way to invoke all commands from only one script on VM1? Commands on VM2 will have to be executed as root. How can I do that without storing my root password as plaintext inside the script. I know I did that some time ago but I forgot how... I hope you can help me. Thanks a lot in advance. ;) Dramatic -- View this message in context: http://old.nabble.com/Request-comments%3A-DRBD-to-cold-BackUp-DMS-with-minimal-DownTime-tp30188891p30188891.html Sent from the DRBD - User mailing list archive at Nabble.com.