(Sorry: I forgot to cc the mailing list) > wouldnt the limiting factor be the read and write times of the drives in regards to rebuilding an array?
I would expect the write BW of a single drive (the one being rebuilt) in sequential access mode to be the limiting factor. If, in a 5 drive RAID-5, a single drive sustains, say, 50 MB/s write BW (and, say, 50MB/s read for simplicity): - time for reading 4 drives in parallel == time for reading 1 drive (e.g., 1...@50mb/s == 5,5 hours) If the data recovery compute time is negligible (I expect it to be), then the time to rebuild a 5 disk RAID5 with 1 TB disks should be better than 6h, provided that the "host" is able to sustain more than 250 MB/s for the disks. If you are using a disk-array (not an entry-level cheapo, but FC ones like IBM DS4800, HP EVA 6000, EMC CX500 or better - these are old models) with no activity other than the rebuilding, it should take less than 6h for a 5x 1TB/drive RAID5, IMO. Regards, -- Paulo Afonso Lopes | Tel: +351- 21 294 8536 Departamento de Informática | 294 8300 ext.10702 Faculdade de Ciências e Tecnologia | Fax: +351- 21 294 8541 Universidade Nova de Lisboa | e-mail: po...@fct.unl.pt 2829-516 Caparica, PORTUGAL _______________________________________________ Beowulf mailing list, Beowulf@beowulf.org sponsored by Penguin Computing To change your subscription (digest mode or unsubscribe) visit http://www.beowulf.org/mailman/listinfo/beowulf
