Ok, let's step back once here. I'm not trying to say that HW raid is right for everyone in every situation. I'm not trying to say SW raid is bad. There are pros & cons.
With HW raid, you can safely enable write caching (assuming you have battery backup) and this costs extra, but it greatly improves performance. Dell PERC ships with battery, and write caching enabled by default. I have measured up to 60x faster performance with the write cache enabled (40mins vs 40secs to mkfs on 1.2Tb) but more normally 4x-5x faster performance, for "normal" sized files, benchmarked with iozone. With SW raid, you have the cheaper solution. Also in the case of ZFS, it can be more flexible than the options otherwise available in the HW raid - PERC for example, only does RAID 0, 1, and 5. While ZFS and others can present more options to the sys admin. If we're talking high performance, high reliability computing: I recommend HW raid, BBU enabled, cache enabled, hotswappable drives. Implement redundancy either in HW or SW. If we're talking simply protection from data loss: I recommend any raid as long as it provides redundancy (not raid 0) and has the ability to notify the admin when a disk goes bad. _______________________________________________ bblisa mailing list [email protected] http://www.bblisa.org/mailman/listinfo/bblisa
