There is one big difference. Linux uses all available memory as a global buffer. Buffers in z/OS are more localized to the job or device. The Linux global buffering makes it difficult to impossible to find a point at which you can be sure that what is on disk is the latest consistent data.
-----Original Message----- From: Linux on 390 Port [mailto:[EMAIL PROTECTED] Behalf Of Post, Mark K Sent: Thursday, October 26, 2006 9:43 AM To: LINUX-390@VM.MARIST.EDU Subject: Re: Backing up zLinux I think you just got yourself into trouble here. I would hardly characterize z/OS as having a "primitive" I/O stack or architecture. Lots of buffering and caching go on there, both in hardware and software. The _real_ difference is that z/OS, just like Linux or z/VM, _always_ has a consistent view of its own data. In a shared DASD environment, this is enforced via serialization techniques, either hardware reserve/release, or software such as GRS, MIM, etc. Without those, backing up one z/OS system from another one would run into similar (but perhaps not as severe) problems with inconsistent data winding up on tape. Mark Post -----Original Message----- From: Linux on 390 Port [mailto:[EMAIL PROTECTED] On Behalf Of Carsten Otte Sent: Thursday, October 26, 2006 7:16 AM To: LINUX-390@VM.MARIST.EDU Subject: Re: Backing up zLinux -snip- I know this is dÃferent with operating systems that have a more primitive IO stack like z/OS, which don't do caching and write behind. For Linux, do always use dm-snapshot or a backup client _inside_ the machine or mount read-only. ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390