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Thread: Additional partitions after RAID10 configuration

  1. #1
    Join Date
    Jun 2011
    Beans
    2

    Question Additional partitions after RAID10 configuration

    Hello, im trying to set software RAID10 (Ubuntu Server 11.04). The drives are 4x 40GB.

    During the installation:

    - Created 2GB partition on every disk for md0 (boot).
    - Created 38GB (rest) partition on every disk for md1 (data) - for now it's just one big partition for testing.
    - Created RAID1 from 2GB partitions (sda1, sdb1, ...), bootable.
    - Created RAID10 from 38GB partitions (sda2, sdb2, ...), EXT4.

    After the installation:

    - Created 1GB swap file on md0 (with mkswap and swapon, added to fstab).
    - Reboot.

    What i was expecting to see is:

    /dev/md0 mounted on /boot, about 2GB total, 1 - 1,5GB used for boot files and swap i made.
    /dev/md1 mounted on /, about 76GB total (38GB x2, because of RAID10), 1 - 1,5GB used for system files.

    What i do see now is::

    df -h result:
    Code:
    Filesystem            Size  Used Avail Use% Mounted on
    /dev/md1               70G  1.1G   66G   2% /
    none                  7.9G  272K  7.9G   1% /dev
    none                  7.9G     0  7.9G   0% /dev/shm
    none                  7.9G   56K  7.9G   1% /var/run
    none                  7.9G     0  7.9G   0% /var/lock
    /dev/md0              1.9G  1.1G  699M  61% /boot
    My questions are:

    (1) What are these 'none' filesystem partitions and why where they created? Why 7.9GB - i didn't set anything like that. Got software RAID1 (2 disks) on different machine and it shows only /dev/mdX, not some additional partitions.

    (2) Why /dev/md1 isn't 76GB total? During the installation all disks were seen as full 40GB, not smaller. Even if it was, it would be about 40GB / 1024 * 1K ~= 39GB, so minus that 2GB for md0 = 37GB ... x2 ~= 74GB, not 70GB. That's not really a problem, im just curious - maybe im mistaken, because my logics are wrong - im more concerned about these partitions.

    (3) How large should be swap partition with this configuration? Everywhere i read, people say '2x your RAM' - it would take half of total disk space here!

    Additional informations:

    fdisk -l
    Code:
    Disk /dev/sda: 40.0 GB, 40018599936 bytes
    255 heads, 63 sectors/track, 4865 cylinders
    Units = cylinders of 16065 * 512 = 8225280 bytes
    Sector size (logical/physical): 512 bytes / 512 bytes
    I/O size (minimum/optimal): 512 bytes / 512 bytes
    Disk identifier: 0x000e86fe
    
       Device Boot      Start         End      Blocks   Id  System
    /dev/sda1               1         244     1951744   fd  Linux raid autodetect
    Partition 1 does not end on cylinder boundary.
    /dev/sda2   *         244        4866    37127168   fd  Linux raid autodetect
    
    Disk /dev/sdb: 40.0 GB, 40018599936 bytes
    255 heads, 63 sectors/track, 4865 cylinders
    Units = cylinders of 16065 * 512 = 8225280 bytes
    Sector size (logical/physical): 512 bytes / 512 bytes
    I/O size (minimum/optimal): 512 bytes / 512 bytes
    Disk identifier: 0x00006d08
    
       Device Boot      Start         End      Blocks   Id  System
    /dev/sdb1               1         244     1951744   fd  Linux raid autodetect
    Partition 1 does not end on cylinder boundary.
    /dev/sdb2   *         244        4866    37127168   fd  Linux raid autodetect
    
    Disk /dev/sdd: 40.0 GB, 40018599936 bytes
    255 heads, 63 sectors/track, 4865 cylinders
    Units = cylinders of 16065 * 512 = 8225280 bytes
    Sector size (logical/physical): 512 bytes / 512 bytes
    I/O size (minimum/optimal): 512 bytes / 512 bytes
    Disk identifier: 0x0002a1bd
    
       Device Boot      Start         End      Blocks   Id  System
    /dev/sdd1               1         244     1951744   fd  Linux raid autodetect
    Partition 1 does not end on cylinder boundary.
    /dev/sdd2   *         244        4866    37127168   fd  Linux raid autodetect
    
    Disk /dev/sdc: 40.0 GB, 40018599936 bytes
    255 heads, 63 sectors/track, 4865 cylinders
    Units = cylinders of 16065 * 512 = 8225280 bytes
    Sector size (logical/physical): 512 bytes / 512 bytes
    I/O size (minimum/optimal): 512 bytes / 512 bytes
    Disk identifier: 0x00018031
    
       Device Boot      Start         End      Blocks   Id  System
    /dev/sdc1               1         244     1951744   fd  Linux raid autodetect
    Partition 1 does not end on cylinder boundary.
    /dev/sdc2   *         244        4866    37127168   fd  Linux raid autodetect
    
    Disk /dev/md0: 1997 MB, 1997524992 bytes
    2 heads, 4 sectors/track, 487677 cylinders
    Units = cylinders of 8 * 512 = 4096 bytes
    Sector size (logical/physical): 512 bytes / 512 bytes
    I/O size (minimum/optimal): 512 bytes / 512 bytes
    Disk identifier: 0x00000000
    
    Disk /dev/md0 doesn't contain a valid partition table
    
    Disk /dev/md1: 76.0 GB, 76033294336 bytes
    2 heads, 4 sectors/track, 18562816 cylinders
    Units = cylinders of 8 * 512 = 4096 bytes
    Sector size (logical/physical): 512 bytes / 512 bytes
    I/O size (minimum/optimal): 524288 bytes / 1048576 bytes
    Disk identifier: 0x00000000
    
    Disk /dev/md1 doesn't contain a valid partition table
    cat /etc/fstab
    Code:
    # <file system> <mount point>   <type>  <options>       <dump>  <pass>
    proc            /proc           proc    nodev,noexec,nosuid 0       0
    # / was on /dev/md1 during installation
    UUID=2c789bfe-5da3-4140-be67-bbf067c879ce /               ext4    errors=remount-ro 0       1
    # /boot was on /dev/md0 during installation
    UUID=890d72b1-6b0c-44e9-8e29-d5d1dc03c217 /boot           ext4    defaults        0       2
    /boot/1Gb.swap none swap sw 0 0
    cat /proc/mdstat
    Code:
    Personalities : [linear] [multipath] [raid0] [raid1] [raid10] [raid6] [raid5] [raid4]
    md1 : active raid10 sdc2[2] sdd2[3] sda2[0] sdb2[1]
          74251264 blocks super 1.2 512K chunks 2 near-copies [4/4] [UUUU]
    
    md0 : active raid1 sdc1[2] sdd1[3] sda1[0] sdb1[1]
          1950708 blocks super 1.2 [4/4] [UUUU]
    
    unused devices: <none>
    Machine

    Intel i5 3.2GHz, 16GB RAM DDR3, these 4 drives are SSD, 40GB each.

    Destination

    Web server (LAMP) with huge database usage (small number of connections, lots of queries).


    I'd really appreciate any information / help.
    Also wanted to say im pretty much 'sunday user' of linux, so if my conception is totally wrong, don't be too hard on me.

    If i should provide any more system information please let me know, i'll do that asap.

    Thank you!
    Last edited by gipson; June 27th, 2011 at 09:34 AM.

  2. #2
    Join Date
    Jun 2011
    Beans
    2

    Re: Additional partitions after RAID10 configuration

    Found info about these 'none' partitions: http://ubuntuforums.org/showthread.php?t=1670124

    Question about how big should be swap file with this configuration still stands, thanks.
    Last edited by gipson; June 28th, 2011 at 01:02 PM.

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