On Thu, 9 Mar 2006, Hugh Sasse wrote:
> > Also enable server mode. enable caching of temp dir
>
> Enabling server mode is not possible given some types of client (from
> my reading of the docs). I don't know all the clients people use, so
> I must err on the side of caution. Or is that paranoid in 2006?
Server mode is only risky under the following circumstrances:
1: Access is made via POP3 and local disk (or a non-compatible imap3 server)
which use non-compatible locking methods.
2: Clients _simultaneously_ access using both methods.
I used server mode for many years in a mixed environment with no
problemss - by ensuring the lock mechanisms used were compatible.
Even without that, it is highly unusual for users to use both pop3 and
local disk access methods - those that do are usually technically savvy
enough to understand the corruption risk and not use both methods
simultaneously once it is explained to them.
> Thanks. I'm not au fait with disk internals, and thought that some
> disks may have many heads
They do (one per platter), but....
>, not just to read one cylinder at a time,
Only one head is ever active at one time with current commonly available
commercial available disk techmology.
The only way to achieve what you want is to use a suitable hardware
controller capable of simultaneously addressing multiple drive busses
(despite the other advantages of scsi, only one drive can be addressed
at a time on any given physical scsi bus.
Large scale (S)ATA or SASI raid controllers give better results most of
the time in terms of overall bandwidth. Latencies cannot be redcued
below seek+rotation times even with fancy controllers.
For ultimate bandwidth andlatencies, suitable solid state arrays are the
only way to go - but are extremely expensive.
--
If a person, or organisation, starts to play on your fears
it may be that person or organisation that you should fear.
