Re: RAIT in 2.4.3b4
2003-01-29 22:30:11
As I was writing the reply to how to mirror to disk and tape, I realized
doing the async I/O is going to be a bit harder to integrate than you
might think.
The RAIT code does not call the OS write() function. Instead, it calls
the tapeio library tapefd_write() call. The reason is that some of
the RAIT segments may not be going to tape at all. So tapefd_write()
may end up calling tape_tapefd_write(), or file_tapefd_write(), or
null_tapefd_write(), or ...
To do this right, we'd probably need to add tapefd_aiowrite() to the
tapeio library and the matching XXXX_tapefd_write() calls to the various
drivers (and the corresponding *aioread() and *aiowait() routines).
That's not a terribly big deal, but it's not the "trivial" case of just
adding a few lines in output-rait.c that one might think.
John R. Jackson, Technical Software Specialist, jrj AT purdue DOT edu
|
<Prev in Thread] |
Current Thread |
[Next in Thread> |
Re: RAIT in 2.4.3b4,
John R. Jackson <=
|
|
|