Determining Disk Space Requirements

The SAM-QFS software requires a certain amount of disk cache (file system devices) to create and manage data files and directories.

Planning Your File System and Verifying Disk Cache

A local file system requires only a single partition. If you install SAM-QFS to enable archiving support, the file system requires either one or two partitions:

• To store file data separately from file system metadata (ma file system), you must have at least two disk devices or partitions.

• To store data and metadata on the same device (ms file system), you must have one disk device or partition.

The disk devices or partitions do not require any special formatting. You might see better performance if you configure multiple devices across multiple interfaces (HBAs) and disk controllers.

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Caution - Ensure that the disks and partitions that you plan to use are not currently in use and that they do not contain existing data. Any existing data will be lost when you create the Sun QFS file system.

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The disks must be connected to the server through a Fibre Channel (FC) or SCSI controller. You can specify individual disk partitions for a disk, or you can use the entire disk as a disk cache. The software supports disk arrays, including those under the control of volume management software such as Solaris Volume Manager.

Before creating your first file system, become familiar with file system layout possibilities. For information about volume management, file system layout, and other aspects of file system design, see the Sun QFS File System 5.3 Configuration and Administration Guide.

Estimating Disk Cache Requirements

Use the following guidelines to estimate the disk cache needed for SAM-QFS software (file systems plus the storage and archive manager):

• Disk cache – The largest file (in bytes) plus the amount of space needed for working files

• Metadata cache – Must have enough space to contain the following data:

  • Two copies of the superblock (16 Kbytes each)

  • Reservation maps for metadata space plus data space ((metadata + file data)/disk allocation unit (DAU)/32,000) * 4 Kbytes

  • Inode space (number of files + number of directories) * 512 bytes

  • Indirect blocks, a minimum of 16 Kbytes each

  • Directory data space (number of directories * 16 Kbytes)

Use the format command to verify that you have sufficient disk cache space. The format command shows how the disks are partitioned and the size of each partition. See the format(1M) man page.

Example 3-1 Using the format Command on Fibre-Channel-Attached Disks

In this example, six disks are attached to a server. Two internal disks are connected by means of controller 0 on targets 10 and 11 (c0t10d0 and c0t11d0). The other disks are external.

The format command output in this example has been edited to improve clarity.

# format
Searching for disks...done

AVAILABLE DISK SELECTIONS:
       0. c0t10d0 <SUN36G cyl 24620 alt 2 hd 27 sec 107>
          /sbus@3,0/SUNW,fas@3,8800000/sd@a,0
       1. c0t11d0 <SUN36G cyl 24620 alt 2 hd 27 sec 107>
          /sbus@3,0/SUNW,fas@3,8800000/sd@b,0
       2. c9t60020F2000003A4C3ED20F150000DB7Ad0 <SUN-T300-0118 cyl 34530 alt 2 hd 48 sec 128>
          /scsi_vhci/ssd@g60020f2000003a4c3ed20f150000db7a
       3. c9t60020F2000003A4C3ED215D60001CF52d0 <SUN-T300-0118 cyl 34530 alt 2 hd 48 sec 128>
          /scsi_vhci/ssd@g60020f2000003a4c3ed215d60001cf52
       4. c9t60020F2000003A4C3ED21628000EE5A6d0 <SUN-T300-0118 cyl 34530 alt 2 hd 48 sec 128>
          /scsi_vhci/ssd@g60020f2000003a4c3ed21628000ee5a6
       5. c9t60020F2000003A4C3ED216500009D48Ad0 <SUN-T300-0118 cyl 34530 alt 2 hd 48 sec 128>
          /scsi_vhci/ssd@g60020f2000003a4c3ed216500009d48a
Specify disk (enter its number):^d
#
# format /dev/rdsk/c9t60020F2000003A4C3ED216500009D48Ad0s2
# format f
partition> p


Part      Tag    Flag     Cylinders         Size            Blocks
  0 unassigned    wm       0 -  4778       14.00GB    (4779/0/0)   29362176
  1 unassigned    wm    4779 -  9557       14.00GB    (4779/0/0)   29362176
  2     backup    wu       0 - 34529      101.16GB    (34530/0/0) 212152320
  3 unassigned    wm    9558 - 14336       14.00GB    (4779/0/0)   29362176
  4 unassigned    wm   14337 - 19115       14.00GB    (4779/0/0)   29362176
  5 unassigned    wm   19116 - 23894       14.00GB    (4779/0/0)   29362176
  6 unassigned    wm   23895 - 28673       14.00GB    (4779/0/0)   29362176
  7 unassigned    wm   28674 - 33452       14.00GB    (4779/0/0)   29362176

partition> ^D
#

Example 3-2 Using the format Command on SCSI-Attached Disks

In this example, four disks are attached to a server. Two internal disks are connected by means of controller 0 on targets 0 (c0t0d0) and 1 (c0t1d0). Two external disks are connected by means of controller 3 on targets 0 (c3t0d0) and 2 (c3t2d0).

# format
Searching for disks...done

AVAILABLE DISK SELECTIONS:
       0. c0t0d0 <SUN9.0G cyl 4924 alt 2 hd 27 sec 133>
          /sbus@1f,0/SUNW,fas@e,8800000/sd@0,0
       1. c0t1d0 <SUN2.1G cyl 2733 alt 2 hd 19 sec 80>
          /sbus@1f,0/SUNW,fas@e,8800000/sd@1,0
       2. c3t0d0 <SUN36G cyl 24620 alt 2 hd 27 sec 107>
          /sbus@1f,0/QLGC,isp@0,10000/sd@0,0
       3. c3t2d0 <SUN36G cyl 24620 alt 2 hd 27 sec 107>
          /sbus@1f,0/QLGC,isp@0,10000/sd@2,0
Specify disk (enter its number): 1
selecting c0t1d0
[disk formatted]
Warning: Current Disk has mounted partitions.

FORMAT MENU:
        disk       - select a disk
        type       - select (define) a disk type
        partition  - select (define) a partition table
        current    - describe the current disk
        format     - format and analyze the disk
        repair     - repair a defective sector
        label      - write label to the disk
        analyze    - surface analysis
        defect     - defect list management
        backup     - search for backup labels
        verify     - read and display labels
        save       - save new disk/partition definitions
        inquiry    - show vendor, product and revision
        volname    - set 8-character volume name
        <cmd>      - execute <cmd>, then return
        quit
format> par

PARTITION MENU:
        0      - change "0" partition
        1      - change "1" partition
        2      - change "2" partition
        3      - change "3" partition
        4      - change "4" partition
        5      - change "5" partition
        6      - change "6" partition
        7      - change "7" partition
        select - select a predefined table
        modify - modify a predefined partition table
        name   - name the current table
        print  - display the current table
        label  - write partition map and label to the disk
        <cmd>  - execute <cmd>, then return
        quit
partition> pri
Current partition table (original):
Total disk cylinders available: 2733 + 2 (reserved cylinders)

Part      Tag    Flag     Cylinders        Size            Blocks
  0        var    wm       0 - 2732        1.98GB    (2733/0/0) 4154160
  1 unassigned    wm       0               0         (0/0/0)          0
  2     backup    wm       0 - 2732        1.98GB    (2733/0/0) 4154160
  3 unassigned    wm       0               0         (0/0/0)          0
  4 unassigned    wm       0               0         (0/0/0)          0
  5 unassigned    wm       0               0         (0/0/0)          0
  6 unassigned    wm       0               0         (0/0/0)          0
  7 unassigned    wm       0               0         (0/0/0)          0

partition> q