Tux3 - mmap and snapshotting

[OGAWA Hirofumi]

Maciej Piechotka <uzytkownik2 at gmail.com> writes:

> Hi,
>
> I've become interested in testing tux3 but I have a few questions before I try 
> it out:
>
> 1. In todo list there was mentioned mmap support. What's happening
> currently on mmap call (does it fail or is it just using for example
> slower emulation by kernel using other entry points)?

For now, if mmap write happens, kernel/fs would be the cause of kernel
panic. mmap read on read-only file should works though.

Because we are not using generic routine in kernel. So, we have to
implement mmap write by our way.

> 2. Is tux3 lvm snapshot safe (i.e. I can create a snapshot while fs is 
> mounted)? I understend that tux3 native snapshotting will be added in future 
> but some form of snapshotting is required by my current backup strategy

For now, we are not caring fsfreeze. So I think it would not be safe, or
it doesn't work.

I'm not checking how many jobs need for fsfreeze support, so I'm not
sure how easy/hard to implement it.

> 3. Have the benchmarks been done using sdd or traditional hdd? How does tux3 
> handles fragmentation if it was sdd?

Benchmarks was done on kvm on host using HDD. Fragmentation avoidance,
and optimize for rotating drive is we are currently working one.

Honestly, we would be still far from production use. tux3 was good on
some benchmark loads before optimizing though.

Thanks.
-- 
OGAWA Hirofumi <hirofumi at mail.parknet.co.jp>