What kind of information is kept in the log? If the RAID5 volume is, for example, 5 columns than 4 columns are data written by the application using the volume, usually a file system and using the file system is the application. So, what is in the RAID5 log is application data and the parity stripe calculated from that data. Many sites will explain the XOR operation to calculate parity.
You can not access a specific stripe in a volume. At best, you could, I guess, use fsdb to examine the log content. Bill 2011/5/9 Asiye Yigit <[email protected]> > Hello; > > I know this section. J > > However, there is no further detail what kind of information is kept here > according to what? > > Best regards; > > > > > > *From:* Tony Griffiths [mailto:[email protected]] > *Sent:* Monday, May 09, 2011 11:34 AM > *To:* Asiye Yigit; [email protected] > *Subject:* RE: RAID-5 LOGGING > > > > Hi > > The RAID5 log is used to recover from a double failure (Disk failure + sys > crash). The RAID5 log is used to log all data and parity writes before > committing them. Following a system crash the log will be replayed to the > volume. There is a section in the admin guide: > > > > > https://sort.symantec.com/public/documents/sfha/5.1sp1/solaris/productguides/html/vxvm_admin/ch01s04s09s04.htm > > > > Cheers > > tony > > > > > > *From:* [email protected] [mailto: > [email protected]] *On Behalf Of *Asiye Yigit > *Sent:* 07 May 2011 17:07 > *To:* [email protected] > *Subject:* [Veritas-vx] RAID-5 LOGGING > > > > Hello all; > > İt is recommended to add raid-5 log device to the volume to recover the > correct data in any case including system crash. > > However, I am trying to understand how the data and parity changes are > logged here? Do you know the structure of this area? > > Data and parity itself couldn't write here, if it is like that those area > should be big enough. > > As far as i know, it is small area. > > What kind of information for each data and parity changes is holdin here to > re-paly the log? > > Regards; > > > > _______________________________________________ > Veritas-vx maillist - [email protected] > http://mailman.eng.auburn.edu/mailman/listinfo/veritas-vx > > -- William (Bill) Havey Symantec Certified HA Professional 917 515-3385
_______________________________________________ Veritas-vx maillist - [email protected] http://mailman.eng.auburn.edu/mailman/listinfo/veritas-vx
