* Brian Kroth <[email protected]> [Mon Dec 20, 2010 at 12:03:44PM -0600]: > Michael Tautschnig <[email protected]> 2010-12-03 21:31:
> > Let me first give a short summary of the context: Modern storage devices > > more > > and more use 4k physical sector sizes instead of the original 512B sector > > sizes. [...] > > To resolve this problem, Microsoft decided to start the first partition at > > 1M=2048*512B=256*4k. According to [2] Linux kernel folks consider it the > > best > > approach to follow this decision. Assuming the list on that page is correct, > > partitioning tools such as fdisk or parted will, by default, already follow > > this > > proposal. > > So how does this affect setup-storage, and why am I asking for additional > > input > > concerning this problem? > > setup-storage uses parted, but it forces partitions to start and end at > > certain > > points instead of leaving parted to choose itself. Consequently we remain > > independent of parted's changes regarding start sectors, but at the same > > time > > also have to take this recent trend into account ourselves: Should > > setup-storage > > follow the trend and make the first partition start at 1M or should we stick > > with 63*512B? [...] > > [1] http://www.infoq.com/news/2010/03/4k-sectors > > [2] https://ata.wiki.kernel.org/index.php/ATA_4_KiB_sector_issues > Sorry for the slow response and if this is too specific to offer any > guidance. > I tend to use a layout basically makes a small (128-256M) /boot > partition, then carves the rest up for LVM to play with. On that LVM I > usually specify a single partition (eg: /home) that I want to be > preserved, but I'll let the rest of it get blown away. With that in > mind, do you think setup-storage tweaks could be made to allow /boot to > perhaps become a little smaller, but then leave enough of the other > partition alone to allow for preserving my /home lv? Well, you can configure size of /boot anyway, so this shouldn't be an issue. Regarding preservation of LVM there are some recent threads on the mailinglist and in Debian's BTS IIRC. Actually, on all non-embedded and non-virtualized systems I'm using something like 2GB for /boot (iff /boot is a separate partition), to have enough space for different kernel versions as well as ISO boot (loopback and memdisk, depending on what I need). This provides the option to have rescue systems as well as firmware/BIOS updates integrated directly within the bootloader. Very comfortable from the sysadmin POV. :) So worrying about possibly losing up to 1MB is definitely out of scope for setup-storage, IMHO. > More generally, I tend to think giving people the option is best. I > like the notion of an align-at argument that defaults to the new value > (4K?), and then send out a big red warning in the changes/release > announcement that says something along the lines of "if you want the old > behavior/preserving to work, set align-at=512B". > Then again, in my own experience preserve has always been a little > finicky anyways. By the time I get around to wanting to completely > reinstall a machine, I probably want to change the layout anyways. A sane default would be good for performance reasons. Having the option to override the alignment if necessary would be nice to force a specific setup that's not matched by the default. Regarding the sane default, I'd go the parted way-of-life (1MB, 4k,..) and if there any open questions we could get in touch with the parted developers and ask for their input. Kind of related BTW, see thread "RFC: future size of embed area in partition labels" on debian.ports/debian.devel.boot, e.g. http://permalink.gmane.org/gmane.linux.debian.ports.bsd/5522 regards, -mika- -- http://michael-prokop.at/ || http://adminzen.org/ http://grml-solutions.com/ || http://grml.org/
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