large raid array and fedora 5 - Hardware

This is a discussion on large raid array and fedora 5 - Hardware ; Hi, I apologize in advance if my question is off-topic and if the question was asked elsewhere. I want to create only one linux partition on a raid 5 array (3.5 TB). I could not do that with fdisk in ...

+ Reply to Thread
Results 1 to 10 of 10

Thread: large raid array and fedora 5

  1. large raid array and fedora 5

    Hi,

    I apologize in advance if my question is off-topic and if the question
    was asked elsewhere. I want to create only one linux partition on a
    raid 5 array (3.5 TB). I could not do that with fdisk in fedora 5. I
    read the net and found out about 2TB size limit.

    However, I have been using a cluster from somewhere in my school and
    with df command I saw that the home directory is a raid array and its
    size is 5.5TB. The cluster is running somekind of linux but I don't
    really know.

    My questions are How can I create a single partition (ext3) on raid 5
    array? What command should I use?

    If it is not possible, any suggestion is welcome.
    Thanks,
    TAT


  2. Re: large raid array and fedora 5

    tat staggered into the Black Sun and said:
    > I want to create only one linux partition on a raid 5 array (3.5 TB).
    > I could not do that with fdisk in fedora 5. I read the net and found
    > out about 2TB size limit.


    Ordinary x86 partition tables are limited in the partition sizes that
    can be specified. 32 bits unsigned max * 512-byte sectors = 2T, I
    think. You will probably need to use a GPT table.

    > I have been using a cluster from somewhere in my school and with df
    > command I saw that the home directory is a raid array and its size is
    > 5.5TB. The cluster is running some kind of linux


    The maximum size of an ext3 filesystem is 2T. They might be using XFS,
    which can handle larger filesystems.

    > How can I create a single partition (ext3) on [a 3.5T] raid-5? What
    > command should I use?


    You can't have an ext3 filesystem that's larger than 2T.

    --
    Really, I'm not out to destroy Microsoft. That will just be a
    completely unintentional side effect.
    --Linus Torvalds
    Matt G|There is no Darkness in Eternity/But only Light too dim for us to see

  3. Re: large raid array and fedora 5

    tat wrote:
    > I want to create only one linux partition on a raid 5 array (3.5 TB). I
    > could not do that with fdisk in fedora 5. I read the net and found out
    > about 2TB size limit.


    > My questions are How can I create a single partition (ext3) on raid 5
    > array? What command should I use?


    One way to skip the 2 TB partition table limit would be not to create any
    partition table at all. As you only want only one single partition,
    instead of mouting a partition like /dev/sda1 you could mount the entire
    disk /dev/sda instead.

    Assuming that your raid disk is called /dev/sda you could do something
    like:

    mkreiserfs /dev/sda
    mount /dev/sda /mnt/hd

    Of course a line in fstab will make mounting more simple.
    I'm not familiar with ext3 or fedora 5. I usually prefer reiserfs, but
    maybe feodora doesn't support reiserfs. If there is some 2 TB limitation
    in ext3 you might have to choose another file system.

    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


  4. Re: large raid array and fedora 5

    Dances With Crows wrote:
    > tat staggered into the Black Sun and said:
    >> I want to create only one linux partition on a raid 5 array (3.5 TB).
    >> I could not do that with fdisk in fedora 5. I read the net and found
    >> out about 2TB size limit.

    >
    > Ordinary x86 partition tables are limited in the partition sizes that
    > can be specified. 32 bits unsigned max * 512-byte sectors = 2T, I
    > think. You will probably need to use a GPT table.
    >
    >> I have been using a cluster from somewhere in my school and with df
    >> command I saw that the home directory is a raid array and its size is
    >> 5.5TB. The cluster is running some kind of linux

    >
    > The maximum size of an ext3 filesystem is 2T. They might be using XFS,
    > which can handle larger filesystems.
    >
    >> How can I create a single partition (ext3) on [a 3.5T] raid-5? What
    >> command should I use?

    >
    > You can't have an ext3 filesystem that's larger than 2T.
    >


    The max size for a ext3 file system is 32TB if you use 8kB block sizes.
    I have several systems with ext3 file systems larger than 4TB.

    mneme # uname -a
    Linux mneme 2.6.19-gentoo-r5 #1 SMP Wed Apr 11 11:23:40 EDT 2007 x86_64
    Dual Core AMD Opteron(tm) Processor 285 AuthenticAMD GNU/Linux
    mneme # df -Th /dev/md/3
    Filesystem Type Size Used Avail Use% Mounted on
    /dev/md/3 ext3 6.4T 594G 5.5T 10% /home/bacula3

    From /usr/src/linux/Documentation/filesystems/ext2.txt:

    Most of these limits could be overcome with slight changes in the
    on-disk format and using a compatibility flag to signal the format
    change (at the expense of some compatibility).

    Filesystem block size: 1kB 2kB 4kB 8kB

    File size limit: 16GB 256GB 2048GB 2048GB
    Filesystem size limit: 2047GB 8192GB 16384GB 32768GB


    --
    Dr. Douglas O'Neal
    Manager, Bioinformatics Center
    Delaware Biotechnology Institute
    (302) 831-3456

  5. Re: large raid array and fedora 5

    Dear Dr. O'Neal,

    Thank you very much for your respond. I also read from wikipeadia that
    ext3 can support up to 32TB with 8KB block size. How can I do it?

    fdisk /dev/sda gives me
    ----
    [root@bcm84-43 ~]# fdisk /dev/sda

    The number of cylinders for this disk is set to 455672.
    There is nothing wrong with that, but this is larger than 1024,
    and could in certain setups cause problems with:
    1) software that runs at boot time (e.g., old versions of LILO)
    2) booting and partitioning software from other OSs
    (e.g., DOS FDISK, OS/2 FDISK)

    Command (m for help): p

    Disk /dev/sda: 3748.0 GB, 3748030054400 bytes
    255 heads, 63 sectors/track, 455672 cylinders
    Units = cylinders of 16065 * 512 = 8225280 bytes

    Device Boot Start End Blocks Id System

    Command (m for help): n
    Command action
    e extended
    p primary partition (1-4)
    p
    Partition number (1-4): 1
    First cylinder (1-188323, default 1):
    Using default value 1
    Last cylinder or +size or +sizeM or +sizeK (1-188323, default 188323):
    Using default value 188323

    Command (m for help): p

    Disk /dev/sda: 3748.0 GB, 3748030054400 bytes
    255 heads, 63 sectors/track, 455672 cylinders
    Units = cylinders of 16065 * 512 = 8225280 bytes

    Device Boot Start End Blocks Id System
    /dev/sda1 1 188323 1512701660+ 83 Linux

    Command (m for help): w
    The partition table has been altered!

    Calling ioctl() to re-read partition table.
    Syncing disks.
    [root@bcm84-43 ~]#
    -----

    So it is 1.5 TB only. I would appreciate your telling me how I can do
    it.

    Many thanks,
    tat


    On May 21, 8:36 am, Douglas O'Neal wrote:
    > Dances With Crows wrote:
    > > tat staggered into the Black Sun and said:
    > >> I want to create only one linux partition on a raid 5 array (3.5 TB).
    > >> I could not do that with fdisk in fedora 5. I read the net and found
    > >> out about 2TB size limit.

    >
    > > Ordinary x86 partition tables are limited in the partition sizes that
    > > can be specified. 32 bits unsigned max * 512-byte sectors = 2T, I
    > > think. You will probably need to use a GPT table.

    >
    > >> I have been using a cluster from somewhere in my school and with df
    > >> command I saw that the home directory is a raid array and its size is
    > >> 5.5TB. The cluster is running some kind of linux

    >
    > > The maximum size of an ext3 filesystem is 2T. They might be using XFS,
    > > which can handle larger filesystems.

    >
    > >> How can I create a single partition (ext3) on [a 3.5T] raid-5? What
    > >> command should I use?

    >
    > > You can't have an ext3 filesystem that's larger than 2T.

    >
    > The max size for a ext3 file system is 32TB if you use 8kB block sizes.
    > I have several systems with ext3 file systems larger than 4TB.
    >
    > mneme # uname -a
    > Linux mneme 2.6.19-gentoo-r5 #1 SMP Wed Apr 11 11:23:40 EDT 2007 x86_64
    > Dual Core AMD Opteron(tm) Processor 285 AuthenticAMD GNU/Linux
    > mneme # df -Th /dev/md/3
    > Filesystem Type Size Used Avail Use% Mounted on
    > /dev/md/3 ext3 6.4T 594G 5.5T 10% /home/bacula3
    >
    > From /usr/src/linux/Documentation/filesystems/ext2.txt:
    >
    > Most of these limits could be overcome with slight changes in the
    > on-disk format and using a compatibility flag to signal the format
    > change (at the expense of some compatibility).
    >
    > Filesystem block size: 1kB 2kB 4kB 8kB
    >
    > File size limit: 16GB 256GB 2048GB 2048GB
    > Filesystem size limit: 2047GB 8192GB 16384GB 32768GB
    >
    > --
    > Dr. Douglas O'Neal
    > Manager, Bioinformatics Center
    > Delaware Biotechnology Institute
    > (302) 831-3456




  6. Re: large raid array and fedora 5

    tat wrote:
    > Disk /dev/sda: 3748.0 GB, 3748030054400 bytes
    > 255 heads, 63 sectors/track, 455672 cylinders
    > Units = cylinders of 16065 * 512 = 8225280 bytes
    >
    > Device Boot Start End Blocks Id System
    > /dev/sda1 1 188323 1512701660+ 83 Linux
    >
    > Command (m for help): w
    > The partition table has been altered!
    >
    > Calling ioctl() to re-read partition table.
    > Syncing disks.
    > [root@bcm84-43 ~]#
    > -----
    >
    > So it is 1.5 TB only.


    You did know about the 2 TB limit of the partition table so what did you
    expect?

    > I would appreciate your telling me how I can do
    > it.


    As I said in my previous post, you can skip fdisk and make a file system
    of the entire disk instead.

    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


  7. Re: large raid array and fedora 5

    tat wrote:
    > Dear Dr. O'Neal,
    >
    > Thank you very much for your respond. I also read from wikipeadia that
    > ext3 can support up to 32TB with 8KB block size. How can I do it?


    As Henrik has pointed out, a DOS partition table is limited to 2TB
    single partitions. You can get around this two different ways. The
    more involved is actually what many of my systems use - software raid
    to combine several partitions into a single file system. If the
    underlying partitions are on a hardware raid, you can stripe them
    with some performance hit. The second option is to use a sun disklabel
    instead of a dos partition, the size limit is much higher in this case.

    Use the -b option to mke2fs to set the block size.
    mke2fs -n -j -L /scratch -b 4096 /dev/md3

    Doug

  8. Re: large raid array and fedora 5

    In comp.os.linux.hardware Douglas O'Neal :
    > Dances With Crows wrote:
    >> tat staggered into the Black Sun and said:
    >>> I want to create only one linux partition on a raid 5 array (3.5 TB).
    >>> I could not do that with fdisk in fedora 5. I read the net and found
    >>> out about 2TB size limit.

    [..]

    >> You can't have an ext3 filesystem that's larger than 2T.


    > The max size for a ext3 file system is 32TB if you use 8kB block sizes.
    > I have several systems with ext3 file systems larger than 4TB.


    > mneme # uname -a
    > Linux mneme 2.6.19-gentoo-r5 #1 SMP Wed Apr 11 11:23:40 EDT 2007 x86_64


    The confusion about those values is, kernel 2.4 didn't handled
    more then 2TB block devices, no matter what FS. This limit has
    been removed with kernel 2.6.

    [..]

    --
    Michael Heiming (X-PGP-Sig > GPG-Key ID: EDD27B94)
    mail: echo zvpunry@urvzvat.qr | perl -pe 'y/a-z/n-za-m/'
    #bofh excuse 20: divide-by-zero error

  9. Re: large raid array and fedora 5

    Thanks Doug and Henrik. I got it work now. I gave up on Fedora 5
    because it produced some weird messages. Installing debian etch was
    very smooth.
    tat

    On May 19, 2:02 pm, Henrik Carlqvist
    wrote:
    > tat wrote:
    > > I want to create only one linux partition on a raid 5 array (3.5 TB). I
    > > could not do that with fdisk in fedora 5. I read the net and found out
    > > about 2TB size limit.
    > > My questions are How can I create a single partition (ext3) on raid 5
    > > array? What command should I use?

    >
    > One way to skip the 2 TB partition table limit would be not to create any
    > partition table at all. As you only want only one single partition,
    > instead of mouting a partition like /dev/sda1 you could mount the entire
    > disk /dev/sda instead.
    >
    > Assuming that your raid disk is called /dev/sda you could do something
    > like:
    >
    > mkreiserfs /dev/sda
    > mount /dev/sda /mnt/hd
    >
    > Of course a line in fstab will make mounting more simple.
    > I'm not familiar with ext3 or fedora 5. I usually prefer reiserfs, but
    > maybe feodora doesn't support reiserfs. If there is some 2 TB limitation
    > in ext3 you might have to choose another file system.
    >
    > 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




  10. Re: large raid array and fedora 5



    tat wrote:

    >Thanks Doug and Henrik. I got it work now. I gave up on Fedora 5
    >because it produced some weird messages. Installing debian etch was
    >very smooth.
    >tat
    >
    >


    Or you could have used "parted" instead of fdisk or the whole disk.
    That is what I use to create partitions larger than 2TB. As DWC stated
    make it a gpt partition table from within parted.

    Steve


+ Reply to Thread