Supposed new 15 partition limit on PATA drives - Slackware

This is a discussion on Supposed new 15 partition limit on PATA drives - Slackware ; A few people that run OpenSuse (or should I say are run by) are claiming that in the *future* PATA drives will be limited to 15 partitions per disk because of libata. They further argue that it will be limited ...

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Thread: Supposed new 15 partition limit on PATA drives

  1. Supposed new 15 partition limit on PATA drives

    A few people that run OpenSuse (or should I say are run by) are
    claiming that in the *future* PATA drives will be limited to 15
    partitions per disk because of libata.

    They further argue that it will be limited on a kernel level which
    doesn't make a lot of sense to me as are they talking about the kernel
    or a lib.

    My quick google search turned up very little of substance on this issue
    and mentioned that the changes would be merged into the 2.6.19 kernel.

    Well I'm using 2.6.21.5 and don't have that problem.

    Also this was in reference to a Suse Beta (10.3) which is a roach motel
    anyway.

    Has anyone heard anything more on this? I'm inclined to think that this
    is a case of a Beta prematurely using a bleeding edge lib related to a
    partially completed project.

    Also the credibility of the persons in question (there are two) is
    highly suspect as they seem to be Suse shills - Ya know the type - never
    compile a kernel, use Yast for everything, must have a GUI installation,
    etc.

    In any event I could continue just fine for the next three years using
    what I have now. I've seen these stumbling blocks develop along the way
    in the past and they get solved usually in a few months.

    --
    Linux Help: http://rsgibson.com/linux.htm
    Email - rsgibson@verizon.borg
    Replace borg with net


  2. Re: Supposed new 15 partition limit on PATA drives

    Ron Gibson wrote:
    > A few people that run OpenSuse (or should I say are run by) are
    > claiming that in the *future* PATA drives will be limited to 15
    > partitions per disk because of libata.
    >


    Dude, seriously, what would you need more than 15 partitions for anyway?
    Typically the limitation is in the hardware, not the kernel.

    For example IDE is hardware limited to four primary partitions,
    one of which can be an extended partition with
    an unlimited number of logical drives. Good enough for
    most people you would think!

  3. Re: Supposed new 15 partition limit on PATA drives

    Chris Sorenson wrote:
    > Ron Gibson wrote:
    >> A few people that run OpenSuse (or should I say are run by) are
    >> claiming that in the *future* PATA drives will be limited to 15
    >> partitions per disk because of libata.
    >>

    >
    > Dude, seriously, what would you need more than 15 partitions for anyway?
    > Typically the limitation is in the hardware, not the kernel.
    >
    > For example IDE is hardware limited to four primary partitions,
    > one of which can be an extended partition with
    > an unlimited number of logical drives. Good enough for
    > most people you would think!


    No. There *is* a limit (at least in the linux driver implementation)
    on the numeber of partitions / logical drives.

    From /usr/src/linux/Documentation/devices.txt:

    3 block First MFM, RLL and IDE hard disk/CD-ROM interface
    0 = /dev/hda Master: whole disk (or CD-ROM)
    64 = /dev/hdb Slave: whole disk (or CD-ROM)

    For partitions, add to the whole disk device number:
    0 = /dev/hd? Whole disk
    1 = /dev/hd?1 First partition
    2 = /dev/hd?2 Second partition
    ...
    63 = /dev/hd?63 63rd partition

    For Linux/i386, partitions 1-4 are the primary
    partitions, and 5 and above are logical partitions.
    Other versions of Linux use partitioning schemes
    appropriate to their respective architectures.

    So there is a limit of 63 partitions per IDE (PATA) disk.
    For SCSI (and SATA) disks the maximum number of partitions is 15.

    Again from /usr/src/linux/Documentation/devices.txt:

    8 block SCSI disk devices (0-15)
    0 = /dev/sda First SCSI disk whole disk
    16 = /dev/sdb Second SCSI disk whole disk
    32 = /dev/sdc Third SCSI disk whole disk
    ...
    240 = /dev/sdp Sixteenth SCSI disk whole disk

    Partitions are handled in the same way as for IDE
    disks (see major number 3) except that the limit on
    partitions is 15.


    If you need more partitions I guess you can always reach the same
    goals -in a more flexible way- by extending the partition schema with
    "logical volumes".


    Regards,

    Kees.

    --
    Kees Theunissen.

  4. Re: Supposed new 15 partition limit on PATA drives

    Kees Theunissen wrote:
    >Chris Sorenson wrote:
    >> Ron Gibson wrote:
    >>> A few people that run OpenSuse (or should I say are run by) are
    >>> claiming that in the *future* PATA drives will be limited to 15
    >>> partitions per disk because of libata.
    >>>

    >> Dude, seriously, what would you need more than 15
    >> partitions for anyway?
    >> Typically the limitation is in the hardware, not the kernel.


    It should also be emphasized that the limitations listed
    below by Kees are all software, not hardware limitations.

    >> For example IDE is hardware limited to four primary
    >> partitions,
    >> one of which can be an extended partition with
    >> an unlimited number of logical drives. Good enough for
    >> most people you would think!

    >
    >No. There *is* a limit (at least in the linux driver implementation)
    >on the numeber of partitions / logical drives.
    >
    > From /usr/src/linux/Documentation/devices.txt:
    >
    > 3 block First MFM, RLL and IDE hard disk/CD-ROM interface
    > 0 = /dev/hda Master: whole disk (or CD-ROM)
    > 64 = /dev/hdb Slave: whole disk (or CD-ROM)
    >
    > For partitions, add to the whole disk device number:
    > 0 = /dev/hd? Whole disk
    > 1 = /dev/hd?1 First partition
    > 2 = /dev/hd?2 Second partition
    > ...
    > 63 = /dev/hd?63 63rd partition
    >
    > For Linux/i386, partitions 1-4 are the primary
    > partitions, and 5 and above are logical partitions.
    > Other versions of Linux use partitioning schemes
    > appropriate to their respective architectures.
    >
    >So there is a limit of 63 partitions per IDE (PATA) disk.
    >For SCSI (and SATA) disks the maximum number of partitions is 15.
    >
    >Again from /usr/src/linux/Documentation/devices.txt:
    >
    > 8 block SCSI disk devices (0-15)
    > 0 = /dev/sda First SCSI disk whole disk
    > 16 = /dev/sdb Second SCSI disk whole disk
    > 32 = /dev/sdc Third SCSI disk whole disk
    > ...
    > 240 = /dev/sdp Sixteenth SCSI disk whole disk
    >
    > Partitions are handled in the same way as for IDE
    > disks (see major number 3) except that the limit on
    > partitions is 15.
    >
    >If you need more partitions I guess you can always reach the same
    >goals -in a more flexible way- by extending the
    >partition schema with "logical volumes".
    >
    >Regards,
    >
    >Kees.
    >
    >--
    >Kees Theunissen.


    --
    Floyd L. Davidson
    Ukpeagvik (Barrow, Alaska) floyd@apaflo.com

  5. Re: Supposed new 15 partition limit on PATA drives

    On Fri, 31 Aug 2007 02:20:19 -0500, Chris Sorenson wrote:

    > Dude, seriously, what would you need more than 15 partitions for anyway?
    > Typically the limitation is in the hardware, not the kernel.


    > For example IDE is hardware limited to four primary partitions, one of
    > which can be an extended partition with an unlimited number of logical
    > drives. Good enough for most people you would think!


    Dude, seriously, why do I need to explain that to you. Dude, seriously,
    that was not the question. Dude, seriously, you are not most people.

    Dude, seriously...

    --
    Linux Help: http://rsgibson.com/linux.htm
    Email - rsgibson@verizon.borg
    Replace borg with net


  6. Re: Supposed new 15 partition limit on PATA drives

    Floyd L. Davidson says:
    >Kees Theunissen wrote:
    >>Chris Sorenson wrote:
    >>> Ron Gibson wrote:


    >>>> A few people that run OpenSuse (or should I say are run by) are
    >>>> claiming that in the *future* PATA drives will be limited to 15
    >>>> partitions per disk because of libata.


    >>> Dude, seriously, what would you need more than 15
    >>> partitions for anyway?
    >>> Typically the limitation is in the hardware, not the kernel.


    >It should also be emphasized that the limitations listed
    >below by Kees are all software, not hardware limitations.


    In some circumstances, such as static-sized databases, separate
    partitions are faster, and more secure.

    >>> For example IDE is hardware limited to four primary partitions,
    >>> one of which can be an extended partition with an unlimited
    >>> number of logical drives. Good enough for most people you would
    >>> think!


    >>No. There *is* a limit (at least in the linux driver implementation)
    >>on the numeber of partitions / logical drives.


    There is a limit on the seating capacity of your Polar Bear
    Steakhouse, as well.

    From "Alaska's Guide to Good Eating."

    "Don't miss eating your fill at Floyd Davidson's Polar Bear
    Steakhouse. Seating available for 110 persons. Open for lunch and
    supper. Note that, for humanitarian/sporting reasons (according to
    Floyd), all Bear are felled with .22L handguns. Note also that some
    have complained that the "Polar Bear Steaks" are really taken from
    garbage-eating Grizz. Nonetheless, Floyd's personal pole-dancing is
    not to be missed."

    cordially, as always,

    rm

  7. Re: Supposed new 15 partition limit on PATA drives

    Chris Sorenson wrote:
    > Dude, seriously, what would you need more than 15 partitions for anyway?
    > Typically the limitation is in the hardware, not the kernel.


    $ df /usr/local/backup/
    Filesystem 1k-blocks Used Available Use% Mounted on
    /dev/hdc20 1189510 954306 173743 85% /usr/local/backup

    bash-2.05# fdisk -l /dev/hdc

    Disk /dev/hdc: 16 heads, 63 sectors, 34960 cylinders
    Units = cylinders of 1008 * 512 bytes

    Device Boot Start End Blocks Id System
    /dev/hdc2 1221 34960 17004960 5 Extended
    /dev/hdc3 1 1220 614848+ 83 Linux native
    /dev/hdc5 1221 1444 112864+ 82 Linux swap
    /dev/hdc6 1445 3476 1024096+ 83 Linux native
    /dev/hdc7 3477 6524 1536160+ 83 Linux native
    /dev/hdc8 6525 7947 717160+ 83 Linux native
    /dev/hdc9 7948 9370 717160+ 83 Linux native
    /dev/hdc10 9371 9574 102784+ 83 Linux native
    /dev/hdc11 9575 14654 2560288+ 83 Linux native
    /dev/hdc12 14655 16889 1126408+ 83 Linux native
    /dev/hdc13 16890 17702 409720+ 83 Linux native
    /dev/hdc14 17703 19125 717160+ 83 Linux native
    /dev/hdc15 19126 19359 117904+ 83 Linux native
    /dev/hdc16 19360 21798 1229224+ 83 Linux native
    /dev/hdc17 21799 24237 1229224+ 83 Linux native
    /dev/hdc18 24238 24847 307408+ 83 Linux native
    /dev/hdc19 24848 25457 307408+ 83 Linux native
    /dev/hdc20 25458 27896 1229224+ 83 Linux native
    /dev/hdc21 27897 28937 524632+ 83 Linux native
    /dev/hdc22 28938 30969 1024096+ 83 Linux native
    /dev/hdc23 30970 32189 614848+ 83 Linux native

    Partition table entries are not in disk order
    bash-2.05#

    > For example IDE is hardware limited to four primary partitions,
    > one of which can be an extended partition with
    > an unlimited number of logical drives. Good enough for
    > most people you would think!


    Yeah, unlimited is enough even for me :-)

    regards Henrik
    --
    The address in the header is only to prevent spam. My real address is:
    hc1(at)poolhem.se Examples of addresses which go to spammers:
    root@localhost postmaster@localhost


  8. Re: Supposed new 15 partition limit on PATA drives

    Ron Gibson wrote:
    > On Fri, 31 Aug 2007 02:20:19 -0500, Chris Sorenson wrote:
    >
    >> Dude, seriously, what would you need more than 15 partitions for anyway?
    >> Typically the limitation is in the hardware, not the kernel.

    >
    >> For example IDE is hardware limited to four primary partitions, one of
    >> which can be an extended partition with an unlimited number of logical
    >> drives. Good enough for most people you would think!

    >
    > Dude, seriously, why do I need to explain that to you. Dude, seriously,
    > that was not the question. Dude, seriously, you are not most people.
    >
    > Dude, seriously...


    Dude, you're messing with his karma man...

    Back to the topic at hand - After reading your post I became curious and
    started looking around. Nothing really conclusive, but it seems that the
    new PATA (still marked as experimental in the kernel) will treat all
    drives as SCSI and are then limited to 15 partitons. Slackware 12.0 with
    the 2.6.21.5 kernel has the PATA stuff as modules (pata_*.ko) so if you
    don't use those modules you won't be affected by its limitations.

    I can't really see this becoming standardized, but who knows, weirder
    things have happened.

    Steve

  9. Re: Supposed new 15 partition limit on PATA drives

    On Fri, 31 Aug 2007 14:37:11 -0400, Steven J Masta wrote:

    > drives as SCSI and are then limited to 15 partitons. Slackware 12.0
    > with the 2.6.21.5 kernel has the PATA stuff as modules (pata_*.ko) so
    > if you don't use those modules you won't be affected by its
    > limitations.


    Yeah, I have no such problem with kernel 2.6.21.5 and Slack 11 or 12 (I
    use that kernel in both).

    > I can't really see this becoming standardized, but who knows, weirder
    > things have happened.


    Naw, after some examination of who said this and what can be found in
    google it appears to be FUD from some of the Suse point and shoot with
    whatever kernel I'm given crowd

    As a matter of fact it's already made high priority for fixing in that
    Suse Beta's bugzilla section.

    They apparently were trying the bleeding edge and got bitten.

    Geez, don't you love some of these people who confuse all Linux with
    a particular packager's errors.

    --
    Linux Help: http://rsgibson.com/linux.htm
    Email - rsgibson@verizon.borg
    Replace borg with net


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