Shadow Copies84 NAS 2000s Administration GuideNote: Use the mountvol command with the /p option to dismount the volume and take it offline.Mount the volume and bring it online using the mountvol command or the Disk Managementsnap-in.Identifying the Storage AreaTo store the shadow copies of another volume on the same file server, a volume can bededicated on separate disks. For example, if user files are stored on H:\, another volume suchas S:\ can be used to store the shadow copies. Using a separate volume on separate disksprovides better performance and is recommended for heavily used NAS devices.If a separate volume will be used for the storage area (where shadow copies are stored), themaximum size should be changed to No Limit to reflect the space available on the storage areavolume instead of the source volume (where the user files are stored).Disk space for shadow copies can be allocated on either the same volume as the source files ora different volume. There is, however, a trade-off between ease of use and maintenance versusperformance and reliability that the system administrator must consider.For example, by keeping the shadow copy on the same volume, although there is a potentialgain in ease of setup and maintenance, there may be a reduction in performance and reliability.Caution: If shadow copies are stored on the same volume as the user files, note that a burstof disk input/output (I/O) can cause all shadow copies to be deleted. If the sudden deletionof shadow copies is unacceptable to administrators or end users, it is best to use a separatevolume on separate disks to store shadow copies.Determining Creation FrequencyThe more frequently shadow copies are created, the more likely that end users will get theversion that they want. However, with a maximum of 64 shadow copies per volume, there is atrade-off between the frequency of making shadow copies and the amount of time that theearlier files will be available.By default, the NAS 2000s will create shadow copies at 0700 and 1200, Monday throughFriday when the feature is enabled for a volume. However, these settings are easily modifiedby the administrator so that the shadow copy schedule can better accommodate end user needs.To modify these schedules see the section on “Shadow Copy Schedules” documented later inthis chapter.Note: The more shadow copies are created, the more disk space the shadow copies can consume,especially if files change frequently.
