HP StorageWorks Storage Mirroring user's guide (T2558-96073, February 2008)

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b. If you are mirroring/replicating from an NTFS source to a FAT target, you may see additional error messages in your
Storage Mirroring log file because the target file system cannot handle the NTFS attributes or file permissions. For
example, if your replication set contains files with alternate data streams, you will see messages indicating that there
are unfinished operations because the FAT file system cannot store the alternate data stream information.
c. If you select a compressed file or folder from an NTFS partition and replicate it to a FAT target, the attributes are
lost, but the data is maintained.
2. If any directory or file contained in your replication set specifically denies permission to the system account or the
account running the Storage Mirroring service, the attributes of the file on the target will not be updated because of the
lack of access. This also includes denying permission to the Everyone group because this group contains the system
account.
3. If you select a dynamic volume and you increase the size of the volume, the target must be able to compensate for an
increase in the size of the dynamic volume.
4. If you select files with alternate data streams, keep in mind the following.
a. Alternate data streams are not included in the replication set size calculation. Therefore, you may see the mirror
process at 100% complete while mirroring continues.
b. The number of files and directories reported to be mirrored will be incorrect. It will be off by the number of
alternate streams contained in the files and directories because the alternate streams are not counted. This is a
reporting issue only. The streams will be mirrored correctly.
c. Use the checksum option when performing a difference mirror or verification to ensure that all alternate data
streams are compared correctly.
d. If your alternate streams are read-only, the times may be flagged as different if you are creating a verification report
only. Initiating a remirror with the verification will correct this issue.
5. If you select encrypted files, keep in mind the following.
a. Only the data, not the attributes or security/ownership, is replicated. However, the encryption key is included. This
means that only the person who created the encrypted file on the source will have access to it on the target.
b. Only data changes cause replication to occur; changing security/ownership or attributes does not.
c. Replication will not occur until the Windows Cache Manager has released the file. This may take awhile, but
replication will occur when Storage Mirroring can access the file.
d. When remirroring, the entire file is transmitted every time, regardless of the remirror settings.
e. Verification cannot check encrypted files because of the encryption. If remirror is selected, the entire encrypted file
will be remirrored to the target. Independent of the remirror option, all encrypted files will be identified in the
verification log.
f. Empty encrypted files will be mirrored to the target, but if you copy or create an empty encrypted file within the
replication set after mirroring is complete, the empty file will not be created on the target. As data is added to the
empty file on the source, it will then be replicated to the target.
g. When you are replicating encrypted files, a temporary file is created on both the source and target servers. The
temporary file is automatically created in the same directory as the Storage Mirroring disk queues. If there is not
enough room to create the temporary file, an out of disk space message will be logged. This message may be
misleading and indicate that the drive where the encrypted file is located is out of space, when it actually may be the
location where the temporary file is trying to be created that is out of disk space.
6. If you are using mount points, keep in mind the following.
a. By default, the mount point data will be stored in a directory on the target. You can create a mount point on the
target to store the data or maintain the replicated data in a directory. If you use a directory, it must be able to
handle the amount of data contained in the mount point.
b. Recursive mount points are not supported. If you select data stored on a recursive mount point, mirroring will
never finish.