I'd say you're about right on the mark after you figure in compression. For example, the minimum speed of an LTO-3 drive is 27 MB/s, and its native speed is 80 MB/s. A T10000 has a native speed of 120 MB/s, but can step down to a native speed of 40 MB/s.
But then you have to add compression. After you add what I'd consider to be an average compression ratio (1.5:1), your 30-35% becomes about 50% of the drive's original advertised native speed. Does that make sense? --- W. Curtis Preston -----Original Message----- From: ADSM: Dist Stor Manager [mailto:[EMAIL PROTECTED] On Behalf Of Richard Sims Sent: Wednesday, May 23, 2007 12:38 PM To: [email protected] Subject: Re: [ADSM-L] Restore Times On May 23, 2007, at 3:21 PM, Paul Zarnowski wrote: > ... LTO2+ has variable speed technology, > which helps, but I think only to a limit. I think there may still be > a point where if the data is being read too slowly, the drive will > stop streaming. From what I've read, drives can reliably reduce speed only to about 50%, so speed-matching is a very limited thing. Collocation and concerted reclamation of serial media need to be in effect to keep restorals as efficient as possible. Reclamation is usually thought of as a means of supplying the scratch pool, but its value as a restoral performance aid needs to also be kept in mind. Richard Sims
