From: David Lang <david.lang@digitalinsight.com>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: 64-bit kdev_t - just for playing
Date: Thu, 3 Apr 2003 02:09:48 -0800 (PST) [thread overview]
Message-ID: <Pine.LNX.4.44.0304030207230.31471-100000@dlang.diginsite.com> (raw)
In-Reply-To: <b6fmoe$nvt$1@cesium.transmeta.com>
when you think of huge raid arrays that present themselves to the system
as a single drive even 64 partitions can be limiting.
I don't really know what an appropriate limit would be, this may be
something that has a default setting for static dev entries and they
dynamic assignments can get more
David Lang
On 2 Apr 2003, H. Peter Anvin wrote:
> Date: 2 Apr 2003 14:03:58 -0800
> From: H. Peter Anvin <hpa@zytor.com>
> To: linux-kernel@vger.kernel.org
> Subject: Re: 64-bit kdev_t - just for playing
>
> Followup to: <200304020931.38671.pbadari@us.ibm.com>
> By author: Badari Pulavarty <pbadari@us.ibm.com>
> In newsgroup: linux.dev.kernel
> >
> > Roman,
> >
> > Here is the patch for sd to allow more than 256 disks.
> > There are few issues with the patch that need to be resolved.
> >
> > 1) With the patch I get 16 bits for minor. Since 4 bits are used for
> > partition, we get 12 bits to represent disks. So each major can support
> > 2^12 =3D 4096 disks. Disks 0 - 4095 are mapped to major=3D8,=20
> > disks 4096 - 8191 to major =3D 65 and so on..
> >
> > This means ..
> >
> > (i) I need to create nodes in /dev/ to match new <major, minor> for=20
> > these disks. Currently "mknod" is broken due to glibc issues with dev_t.
> >
> > (ii) We need to worry about backward compatibility. For example:
> > 17th disk used to have <65, 0>. Now its major, minor is <8, 256>.
> > So /dev/ entires need to be re-created to match these, everytime
> > you reboot 2.4/2.5 etc. Greg KH udev might fix this for us.=20
> >
> > 2) Do we still need 16 majors for disks ?
> >
>
> No, we don't. On the other hand, we really should change to 64
> partitions/disk, same as for non-SCSI disks. 16 really is too small.
>
> -hpa
>
> --
> <hpa@transmeta.com> at work, <hpa@zytor.com> in private!
> "Unix gives you enough rope to shoot yourself in the foot."
> Architectures needed: ia64 m68k mips64 ppc ppc64 s390 s390x sh v850 x86-64
> -
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
>
next prev parent reply other threads:[~2003-04-03 10:01 UTC|newest]
Thread overview: 80+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-03-31 23:41 64-bit kdev_t - just for playing Badari Pulavarty
2003-03-31 23:54 ` William Lee Irwin III
2003-03-31 23:55 ` Joel Becker
2003-04-02 12:18 ` Roman Zippel
2003-04-02 17:31 ` Badari Pulavarty
2003-04-02 22:03 ` H. Peter Anvin
2003-04-03 10:09 ` David Lang [this message]
2003-04-03 11:14 ` Lars Marowsky-Bree
2003-04-03 12:13 ` Roman Zippel
2003-04-03 13:37 ` Andries Brouwer
2003-04-03 14:01 ` Roman Zippel
2003-04-07 15:02 ` H. Peter Anvin
2003-04-07 20:10 ` Roman Zippel
2003-04-07 21:57 ` Roman Zippel
2003-04-07 22:43 ` Kevin P. Fleming
2003-04-08 15:22 ` Roman Zippel
2003-04-08 22:53 ` Werner Almesberger
2003-04-08 23:11 ` David Lang
2003-04-08 23:47 ` Werner Almesberger
2003-04-08 23:58 ` Kevin P. Fleming
2003-04-08 23:56 ` H. Peter Anvin
2003-04-08 23:06 ` Andrew Morton
2003-04-09 0:40 ` Roman Zippel
2003-04-09 1:02 ` Joel Becker
2003-04-09 1:25 ` Roman Zippel
2003-04-09 16:42 ` Roman Zippel
2003-04-09 0:21 ` Roman Zippel
2003-04-11 9:58 ` Pavel Machek
2003-04-08 15:29 ` Roman Zippel
-- strict thread matches above, loose matches on Subject: below --
2003-04-09 18:40 James Bottomley
2003-04-09 20:54 ` Roman Zippel
2003-04-10 2:19 ` James Bottomley
2003-04-10 12:47 ` Roman Zippel
2003-04-10 15:30 ` James Bottomley
2003-04-10 23:53 ` Roman Zippel
2003-04-11 0:01 ` David Lang
2003-04-11 0:17 ` Roman Zippel
2003-04-11 0:47 ` Joel Becker
2003-04-11 1:11 ` Roman Zippel
2003-04-09 18:36 Andries.Brouwer
2003-04-09 21:11 ` Roman Zippel
2003-04-01 18:32 Andries.Brouwer
2003-03-28 15:33 Andries.Brouwer
2003-03-28 15:49 ` Roman Zippel
2003-03-28 11:46 Andries.Brouwer
2003-03-28 11:57 ` Roman Zippel
2003-03-28 11:10 Andries.Brouwer
2003-03-28 11:36 ` Roman Zippel
2003-03-30 20:05 ` H. Peter Anvin
2003-03-30 20:13 ` Roman Zippel
2003-03-27 22:37 Andries.Brouwer
2003-03-27 22:55 ` Roman Zippel
2003-03-27 20:27 Andries.Brouwer
2003-03-27 22:12 ` Roman Zippel
2003-03-27 22:55 ` Alan Cox
2003-03-27 23:19 ` Roman Zippel
2003-03-27 23:48 ` Greg KH
2003-03-28 9:47 ` Roman Zippel
2003-03-28 18:05 ` Joel Becker
2003-03-28 18:48 ` Roman Zippel
2003-03-31 8:31 ` bert hubert
2003-03-31 8:52 ` Roman Zippel
2003-03-31 17:24 ` Joel Becker
2003-03-31 21:32 ` Roman Zippel
2003-03-31 22:18 ` Alan Cox
2003-03-31 23:42 ` Roman Zippel
2003-04-01 14:42 ` Alan Cox
2003-04-01 16:35 ` Greg KH
2003-04-02 13:02 ` Roman Zippel
2003-04-01 14:42 ` Alan Cox
2003-04-01 16:52 ` Christoph Hellwig
2003-04-01 21:59 ` H. Peter Anvin
2003-04-02 7:12 ` Christoph Hellwig
2003-04-02 7:22 ` H. Peter Anvin
2003-03-31 23:45 ` Joel Becker
2003-03-31 23:07 ` Joel Becker
2003-03-31 23:35 ` Roman Zippel
2003-03-27 1:09 Andries.Brouwer
2003-03-27 19:23 ` Roman Zippel
2003-03-30 20:10 ` H. Peter Anvin
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=Pine.LNX.4.44.0304030207230.31471-100000@dlang.diginsite.com \
--to=david.lang@digitalinsight.com \
--cc=hpa@zytor.com \
--cc=linux-kernel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).