Kbase 12362: Accessing Databases Using Remote File Systems -- Cautions
| Autor |
Progress Software Corporation - Progress |
| Acesso |
Público |
| Publicação |
16/10/2008 |
|
Status: Unverified
SYMPTOM(s):
File <filename> is on a remote system (2226)
Database integrity CANNOT be guaranteed for this session. (2227)
setrmode: Couldn't open <file-name> for synchronous I/O. (1114)
bktrunc: Could not open <file-name> for synchronous I/O. Error <err>. (1121)
Could not access mounted file system list, errno = . (2864)
CAUSE:
It is DANGEROUS to store your database or database extents (.db, .d1, .d2, etc.), before-image (.bi), or after-image (.ai) files on remote file systems such as Network File System (NFS).
This problem also pertains to Windows, wherein remote file access can be achieved using either mapped drives, or UNC's.
PROGRESS cannot produce reliable I/O to such files. Therefore, the write-ahead logging protocol used by the PROGRESS database manager does not work, and crash recovery IS LIKELY TO FAIL. As a result, your database is unusable.
For example, on a LAN, if the database, before-image, or after-image files are not on the workstation's local hard disk, but the network file server's disk(s) are being used, you run the risk that in the case of a system crash, your database will be trashed, and PROGRESS will not recover from the errors.
Per Progress Development "If you put any of your database, bi, or ai files on a remotely mounted disk, crash recovery WILL NOT WORK when the system fails."
If PROGRESS detects that certain files are not on a local file system, it generates warning or error messages, such as one of those listed in the Symptoms.
However, PROGRESS does not prevent you from operating in this type of configuration -- do so at your own risk.
FIX:
To access databases on disks connected to a computer different from the one running an application, you MUST start a PROGRESS database server on that computer and access the database through a network connection to the server.