Re: PATCH: Raw device IO for 2.1.131

Matthew Brown (mbrown@smartpages.com)
Tue, 15 Dec 1998 11:33:17 -0800 (PST)


Harald Milz writes:

> Linus, the point is that there _are_ applications out there which do use raw
> devices on other Unix variants, like Oracle, Sybase, etc. If I go to a
> customer and want to sell a Linux solution, and Oracle told him "well we do
> support Linux but it's suboptimal compared to HP, Sun because we can't use
> raw devices" who is going to tell the customer he is in good hands? Is it
> you? Or are you going to tell the customer what is good for him? Just like
> IBM did in the past (and sometimes, still today?) This is arrogant.

> There is more to selling Unix than just technical issues.

I don't presume to answer for Linus, but there are several points
here:

1) Linus and most of us are not being paid for this, and we are not
doing this to sell. There *are* only technical issues.

2) I'm sorry, but part of being a professional *is* telling the
customer what's good for them. It's called professional
integrity.

3) Isn't 'telling the customer what's good for them' exactly what
Oracle et al. would be doing here?

4) Linus has made it clear a number of times on this issue that he
doesn't think raw disk device access is a good idea, and he's not
prepared to add such a feature to the kernel just because 'everyone
else does it'.

> But there _is_ another technical issue nobody mentioned so far in this
> thread. Using e.g. Oracle on raw devices saves you from doing a fsck in a
> high availability failover situation, and this is good for the overall
> uptime customers want to see. LFS/JFS is in the works but still far from
> production ready. At the end of the day we need both features to be able to
> compete, and heck, we are competing.

Well, you could still use a partition like /dev/sda1 for a database --
the only issue is that this goes through the buffer cache instead of
reading or writing directly to the disk.

-Matt

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