105Chapter C - Quick-SetupDepending on how large the disk array is, this check may take quite a time, however, it canbe aborted by pressing . Parity Verify is a diagnosis function which enables you toverify the consistency of a disk array every now and then. We interrupt the verifi cation bypressing . Note: The GDT monitor program GDTMON also includes the parity verifyfunction. Unlike in GDTSETUP, the disk arrayís parity can be checked while the disk array isfully operational (e.g. in a NetWare file server). Further information on GDTMON is given ina separate chapter of this manual.Partial step 5: Simulating a drive failureThis part of our example is optional. Nevertheless, we recommend that you go through it. Itgives you a better understanding of how RAIDYNE reacts in the event of a drive failure andwhat you have to do in such a case.Important: To carry out the drive failure simulation, the disk array must be in the readystatus. Only in this status is there redundancy.In order to make the simulation as realistic as possible, we suggest creating a MS-DOS-partition on the disk array with FDISK. To create disk activity, write a small batch programwhich copies data from one directory of this partition to another. While the copy process isgoing on, we simulate a drive failure of drive DISK_B2 by removing the drive's DC powersupply cable. (If you choose to let another drive fail, please keep in mind the infor mationon the SCSI-bus termination given in Step 1). Now we can observe how RAIDYNE reacts:1. After a short time, the acoustical alarm of the GDT is activated. (Note: this alarm is onlyactivated when the RAID 5 array drive is being accessed).2. RAIDYNE activates the so-called fail operation status during which the disk array remainsfully operational. The data of the failed drive is calculated by means of the redundantdata stored on the other drives.
