Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
I'm wondering if the new kernel option "drop_caches" would allow read only access to the secondary? http://linux.inet.hr/proc_sys_vm_drop_caches.html The reason I want this is for the following scenario * Primary machine has a small DRDB partition with the Postgres "write ahead log" (perhaps stored in a battery backed RAM disk for performance) * Secondary machine has a copy of the PG database, and, as long as it can READ the write ahead log mirror (DRBD or Raid1), it can keep a hot remote ACID compliant backup of the postgres database. Something like this on the secondary while true do mount -o ro /mnt/pg_wal process new WAL entries (this is a read only op, on what is basically a sequential file that just gets added to by the primary) umount /mnt/pg_wal echo 3 > /proc/sys/vm/drop_caches # see below sleep 2 done Here's the details from the above link, about the new proc option. Can anyone give me any feedback on whether this is a viable option? ------------------------ drop_caches Writing to this will cause the kernel to drop clean caches, dentries and inodes from memory, causing that memory to become free. To free pagecache: * echo 1 > /proc/sys/vm/drop_caches To free dentries and inodes: * echo 2 > /proc/sys/vm/drop_caches To free pagecache, dentries and inodes: * echo 3 > /proc/sys/vm/drop_caches As this is a non-destructive operation and dirty objects are not freeable, the user should run "sync" first. Dr. Volker Jaenisch wrote: > Hi DRBD People! > > drbd0.7 is in production on some of our customers sites. > Thank you very much for this fine pice of software. > > Now we are curious on DRBD8. > We have a testing instance of drbd8-pre3 running smootly on two debian > etch servers ACTIVE/PASSIVE. > Is there any documentation to setup ACTIVE/ACTIVE yet? > Please give us some hints to satisfy our curiousity. > > Best Regards > > Volker >