Mike Christie, on 02/25/2009 08:38 PM wrote: > Another reason a lot of distros do not support it is because a common > problem we always hit is that users will write out some data, then start > modifying it again. But the kernel will normally not do do a sync write > when you do a write. So once the write() returns, the kernel is still > sending it through the caches, block, scsi, and iscsi layers. If you are > writing to the data while the it is working its way through the iscsi > layers, the iscsi layer could have done the digest calculation, then you > could modify it and now when the target checks it the digest check will > fail. And so this happens over and over and you get digest errors all > over the place and the iscsi layers fire their error handling and retry > and retry, and in the end they just say forget it and do not support > data digests.
During testing of iSCSI-SCST with data digests enabled with open-iscsi initiator I've regularly once in several hours seen data digests errors. I was going to investigate it, but had no time. Now I know the reason. Thanks for the explanation! Vlad --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "open-iscsi" group. To post to this group, send email to open-iscsi@googlegroups.com 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 -~----------~----~----~----~------~----~------~--~---
