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: http://www.atnf.csiro.au/vlbi/dokuwiki/doku.php/correlator/rebuild
Дата изменения: Unknown Дата индексирования: Sun Apr 10 21:21:04 2016 Кодировка: IBM-866 Поисковые слова: mdi |
If, upon start up (or at any other time, although this is highly unlikely) you experience a disk failure in a set of VLBI disks, fear not! The disk sets are built using RAID5, which is a striping protocol wherein a 7-disk set in which any one disk fails can still have all its data retrieved. This leads to a loss of storage space, but given these disks are shipped around Australia using road freight, we think it's a loss well worth taking!!
Hopefully you won't need to deal with a fully un-initialised disk set. If you do, see Creating XRAIDs.
The rebuilding process involves only the XRAID firmware, and not the I/O on the fibrechannel, so a disk failure does not stop you using the disk set immediately, but you should begin the rebuild as soon as you detect a failure.
NOTE, simply removing a disk, or having a red light, is enough to destroy the disk's membership in a RAID, and so regardless of whether cleaning and reinserting the disk is successful (ie you can select the disk in the XRAID admin tools), you'll still need to rebuild the array. THE RED LIGHT WILL NOT GO OUT but the alarm does turn off.
It is only if two or more disks fail on the one start-up that you will lose all your data. Insert disks carefully!!!