[mythtv-users] USB Flash Memory for boot/system. What is fast enough?
Brian Wood
beww at beww.org
Mon Nov 23 16:28:39 UTC 2009
On Monday 23 November 2009 09:09:47 Greg Cope wrote:
> I would argue that for an FE you should only tun things for playback
> implying that they should not be swapped out.
>
> However I see no technical reason why you could npt have swap on
> flash, and with it's low seek tume flash is actually quite suited to
> it. Windows ready boost is using it in this way (ie extending VM).
The only problem I see is if you are making very heavy use of swap it might
wear out the flash device, but if you are swapping that much you need more
RAM anyway.
>
> > I'm not sure what the noatime parameter would do with a swap
> > partition, it's
> > intended to eliminate writing the access time each time a file is
> > accessed on
> > a normal file system, but swap is not handled as a normal filesystem.
>
> Noatime will do nothing for swap.
That's what I suspected, thanks for confirming it. I'm surprised the system
even accepts that parameter for a swap partition.
>
> > If it's not causing any problems it certainly couldn't hurt, but I
> > would try
> > to get swap off a flash device, either by eliminating it entirely if
> > you can,
> > or writing it to a standard HDD partition, or even use an NFS-
> > mounted file.
> >
> > Swap can be enabled on either a partition or a file, as you probably
> > know.
> >
> > Perhaps someone with a better understanding of how the kernel
> > handles swap
> > will have better suggestions?
> >
> > --
>
> You can trun down swappyness or run with none at all as long as you
> have enough memory to run all the bits you need. Otherwise when the
> kernel gets desperate it will run an OOM killer that usually zaps
> something important. Memory is pretty cheap.
>
> Netbooting is usually easy to configure and update. Once running in a
> ram disk things are usually pretty fast. You then avoid any USB
> storage issues and the CPU overhead of USB storage (Scsi emulation
> etc...)
>
> Having said that if you are not going to run nfs and or this is for a
> backend flash can be ok as long as you get a reliable stick. If
> anyone has any recomendations bar the patriot xts pls share!
That's why I get frustrated when they supply such minimal specs for the
devices. Some have better wear-leveling algotithms than others, but I guess
you can't expect a vendor to advertise "crappy wear leveling".
Sometimes different devices with identical capacity have vastly different
prices, but I never know if a higher price indicates a better device or a
greedier vendor.
--
Brian Wood
beww at beww.org
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