cgould Posted September 10, 2003 Report Share Posted September 10, 2003 I am considering switching from VXA tape backups to file backups using external Firewire hard drives. Although backup performance (speed) is not my reason for switching, I had expected to see some improvement with most any device comparison of tape to hard drive. Out of curiosity, I ran a few quick speed tests backing up to the startup drive for Retrspect server. I was surprised to see it perform a bit slower than tape, about 10 - 20% (eg, 200 mg/min vs. 170 mg.min). Nothing conclusive there - the drive is 3-4 yrs old and needs defragging, I'm still using Retrospect 4.3 and would upgrade to 5.x for file backups, etc. - and I could even live with that kind of speed, but I wonder what others have experienced. Or does it seem I must be missing something important in my configuration? Also, what should I look for when shopping for hard drives as backup devices? I'm planning to use cheap Firewire externals in the 160 - 250 gig range. Their availabilty is what promts me to switch, so anything that would cost a lot more for only a minor speed gain would defeat the purpose. But, for example, does buffer size make any difference, or might I just as well get a 2 mb buffer drive as an 8 mb one? Link to comment Share on other sites More sharing options...
natew Posted September 11, 2003 Report Share Posted September 11, 2003 Hi It may be compression that is slowing things down. Your VXA handled compression in hardware. With a file backup set the CPU has to do it. Retrospect is going to run as fast as the hardware will allow. I would look for a fast external drive. 7200RPM is a must in my book. I have both an 8MB and 2MB cache drive and I don't see much difference. I'm sure there is some but it is not nearly as dramatic as the difference between 512K and 2MB. Nate Link to comment Share on other sites More sharing options...
cgould Posted September 11, 2003 Author Report Share Posted September 11, 2003 Thanks, Nate. I left software compression turned off for the hard drive speed test. The drive was anIBM Deskstar(DTLA-307075) 76.8GB EIDE 7200RPM, UDMA100, 8.5MS, 2MB Cache. Similar specs afterall to the externals I've been considering. Link to comment Share on other sites More sharing options...
natew Posted September 12, 2003 Report Share Posted September 12, 2003 Hi That is a good drive - what kind of load is on the CPU when the backup is running? Nate Link to comment Share on other sites More sharing options...
cgould Posted September 16, 2003 Author Report Share Posted September 16, 2003 (Sorry for the late reply.) Other than running Retrospect 4.3, of course, the CPU runs AppleShareIP 6.3. Activity is very light and infrequent, and I observed that no one was even connected during the speed test. I, however, was connected via Timbuktu Pro 5.2.4, which I use to remotely operate Retrospect. As for the broader question, Nate, would you expect a Firewire external hard drive to perform about the same as VXA tapes, or faster? Have you had any direct experience with this? Thanks. Link to comment Share on other sites More sharing options...
natew Posted September 18, 2003 Report Share Posted September 18, 2003 Hi You may want to try this with Appleshare turned off. Apple share doens't like to play nice with Retrospect in a lot of cases. Your question about speed is a tough one. Personally I would try this on another machine too just to make sure. I suspect the biggest bottleneck in your case is firewire and not the device itself. My feeling is the hard disk is faster especially when you consider the time it takes to rewind or position a tape. The firewire VXA drives are really nice though - a much better choice if you are looking to rotate media. Nate Link to comment Share on other sites More sharing options...
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