>>> Joachim <dav.pin...@gmail.com> schrieb am 06.07.2011 um 18:45 in Nachricht <eec86689-0a67-40f6-bc19-b617274ec...@x12g2000yql.googlegroups.com>: > Hello, > > I am currently trying to implement an iscsi target driver for a remote > storage space with tgt. > > At first, the driver was slow (quite normal), but worked quite well, > with a testing script i wrote. > Then, I added some features for it to get faster, and thus the problem > appeared. > > Actually, after the login to the target with iscsiadm, I partition the > disk, create some filesystem, and then make a copy of a random file > tree, before umounting the partition, and logout. > When i try to mount the partition again (after all required > manipulations with iscsiadm), i stumble upon a series of IO Errors, > meaning that my filesystem is totally corrupted, and that some of the > data weren't saved by my driver (be it that i didnt receive it or that > i could not save it) > > When I use the sync command before umounting, I actually succeed to > read the whole file system again afterwards.
Usually "umount" should sync that filesystem's data, and probably wait until that finished. I don't thin that iSCSI adds another buffering layer that could hold back data between unmount and iSCSI logout. Ulrich > > While searching a solution, I found this in another thread of this > mailing list (http://groups.google.com/group/open-iscsi/browse_thread/ > thread/e445471fab2af459/b8fae3dfb6e6c68f?pli=1) : > > >> is the Sync cache that occurs at logout actually sending data? or is > >> it just sending a scsi msg to flush/checkpoint the target side? > > > >No data. It is just telling the target side to basically flush what it > >has in its cache. For example tgt does a sync() to write out data to the > >backing store. I believe IET does the equivalent of a sync() but it is > >done from the kernel since IET is implemented there. Look at the source > >for IET or just fire off a mail to that list if you want to know all the > >details of what it does. > > > If i'm not misunderstanding what's written here, That means that when > i type the command > $ iscsiadm --mode node --targetname mytarget --logout > All that is done is actually sending a sync command to the target (tgt > in my case) without sending any data relating to the system/iscsid > cache ? > > My hypothesis is thus that my problem originates from this behavior of > the iscsiadm logout action. If I'm not wrong about that, how can i > make it so that a synchronization is done before the iscsi logout ? Or > I am completely wrong, and then do you have any insight as to what my > problem really is ? > > > Thanks for your help in advance ! -- You received this message because you are subscribed to the Google Groups "open-iscsi" group. To post to this group, send email to firstname.lastname@example.org. To unsubscribe from this group, send email to open-iscsi+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/open-iscsi?hl=en.