On Thu, 2009-09-03 at 10:25 -0700, Saibabu Devabhaktuni wrote: > We currently use rsync to create an Oracle standby on a target box > from an existing standby by copying all the datafiles while the source > standby is in recovery status. We are occasionally running into > datafile corruptions being reported by oracle when it is recovering > the new standby. Oracle support says they don't recommend copying > files while the changes being applied to them unless the database is > put in backup mode (which is not possible for us). > > We are using "rsync -av --password-file=pass.secret > source_data_file_name ora...@target::ORCL/" > > We are planning to use "rsync -av --password-file=pass.secret > --block-size=8192 source_data_file_name ora...@target::ORCL/" > > This is because, we are using 8k block size for Oracle and hence the > blocks will be copied in full by rsync to avoid fractured block > copies. Am I correct in this assumption by using "--block-size" > option?
No. --block-size sets the block size for the delta-transfer algorithm; rsync does not provide a way to set the size of its read(2) calls. And even if it did, it would appear from the following message that read(2) calls are not atomic on Linux: http://marc.info/?l=linux-kernel&m=107375454908544 I would recommend looking into a block-device-level snapshot facility such as LVM snapshots. (Note: a similar issue was discussed in this thread: http://lists.samba.org/archive/rsync/2009-May/023270.html but the non-atomicity of read(2) calls was not considered.) -- Matt -- Please use reply-all for most replies to avoid omitting the mailing list. To unsubscribe or change options: https://lists.samba.org/mailman/listinfo/rsync Before posting, read: http://www.catb.org/~esr/faqs/smart-questions.html
