Optimizing Storage Disk Capacity

There are several options for increasing the capacity of your storage disks. The following is a list of options you can use to improve your file system storage capacity:

• Enable block suballocation if you are using the traditional NetWare file system. This eliminates having unused data blocks on your volumes. This feature works only on traditional partitions and volumes. Block suballocation is enabled by default, but can be disabled when the volume is created. If block suballocation has been disabled, enable it in ConsoleOne^TM when you create a partition. For information about enabling block suballocation, see Creating a Partition in the Novell Storage Services Administration Guide. Once block suballocation is enabled, you cannot disable the feature without recreating the volume.
  
  If you use block suballocation, set your file block size to 64 KB. The larger block size causes the system to transfer more data at one time so it improves performance.
  
  Keep at least 1000 free blocks on each NetWare volume that has suballocation enabled. Free blocks are disk blocks that have no files stored in them. If the number of free blocks is low, the suballocation will increase server utilization.
  
  To find the number of free blocks, in MONITOR select Available Options > Volumes. Select the name of the volume you want. Press Tab to expand the information window and note the value of the Free Blocks statistic. For instructions on using MONITOR, see MONITOR in Utilities Reference.
• You can save partition space and increase performance by eliminating the Hot Fix^TM redirection area on a partition. However, once Hot Fix is eliminated from a partition, you cannot add it again without first deleting the volumes on the partition. Once Hot Fix is gone, the partition will no longer be fault tolerant, unless the hard disk itself provides a means of fault tolerance. Data on corrupted sectors of the disk won't be redirected to the Hot Fix redirection area. In addition, you will not be able to mirror the partition.
• Turn off Read-After-Write-Verify in MONITOR. For instructions on using MONITOR, see MONITOR in Utilities Reference.

  Read-After-Write-Verify is almost always provided by the hard disk itself. Use the Read-After-Write-Verify feature in MONITOR only if your hardware does not provide this feature but does support software-controlled Read-After-Write-Verify.

  See Turning Off Read-After-Write Verification.

• If you have a 16-bit disk adapter, make sure you increase the number of reserved buffers below 16 MB. Use the SET command or MONITOR to set the parameter Reserved Buffers Below 16 MB to its upper limit, 300. The parameter is found in MONITOR > Available Options > Server Parameters > Memory. Remember that too many reserved buffers can prevent large volumes from mounting. As soon as possible, upgrade the system to a newer board that can access higher memory. For instructions on using the SETcommand, see SET in Utilities Reference. For instructions on using MONITOR, see MONITOR in Utilities Reference.
• Use a driver that supports scatter gather functionality.
• Provide at least one device large enough to hold a core dump of the server's memory. A core dump cannot span devices.
• If a volume is comprised of two or more segments, each segment should be on a different disk. If the volume is made of more than one segment on one disk, the volume spans between the two segments, slowing performance.
• If you use file compression, make sure you enable the option at a time when there is little server activity.

  For example, make sure that the Deleted Files Compression Option parameter is not set to 2, which would cause compression whenever a file is deleted but not purged. Make sure that users have not flagged their directories IC, which enables immediate compression. Use the SET command to make sure that compression is scheduled to start and stop at the appropriate times.

• You can enable fault tolerance protection by mirroring or duplexing the SYS volume, because it contains the core NetWare files. See Mirroring and Duplexing Partitions.
• Keep 10% free space in any NetWare volume, except SYS where there should be 20% free space.

  WARNING:  Do not fill up your SYS volume. This could damage your entire file system. The Transaction Tracking System, which protects NDS^®, will shut down compromising the NDS replicas on the server.

  To keep enough free space on volumes, try the following suggestions:

  • Use MONITOR to check each volume's disk space regularly.
  • Use the Volume Low Warning Threshold parameter to specify when you will be warned that a volume is running out of disk space. Set the parameter in MONITOR. For instructions on using MONITOR, see MONITOR in Utilities Reference.
  • Move any user files or print queues to another volume.
  • Don't store replicas on servers with low disk space.
  • CD-ROM drives can create large index files. Don't use or mount the CD-ROM unless you have enough space.
  • Limit the size of auditing files. (Auditing works only on traditional NetWare partitions.)