On Jan 3, 2014, at 5:52 PM, LuKreme <[email protected]> wrote: > On 03 Jan 2014, at 14:24 , Dinse, Gregg (NIH/NIEHS) [V] <[email protected]> > wrote: > >> Can you explain why you think RAID-0 > > The failure rate on modern hard drives is too high for me to be at all > comfortable with RAID-0. The only RAID-0 device that I have I am pulling all > the data off and have lost about 3% of the files on it due to read errors. > I’ll be reformatting it as a RAID-5 as soon as I’ve gotten everything off I > can. I was only using the RAID0 to store TV show caps and movie rips, but I > made the mistake on thinking the data was easily replaceable or ephemeral. It > was, but the time lost was significant. > > My current opinion is that RAID0 should never be used for anything other than > temporary storage of working files. For example, if you have a large video > project, keep your clips on a NAS or RAID5 (or 6, or 10) and then use a RAID0 > as your scratch disk for processing that video and rendering. Copy the final > product off the RAID0 as soon as you can to backups or other storage. Never > rely on RAID0 for your data, nothing that is not transient in nature should > be stored there. If you think, even for a second, that losing the data on a > RAID0 would be more than a very slight inconvenience, don’t use it. > >> is a poor choice for the HDDs in my Mac Pro? I thought this would increase >> both speed and capacity. > > Yes, it will, but there’s no error checking, there’s no redundancy, and not > to start channeling Siracusa here, but if your raid is HFS+ then… well, no, > just no. > > I think RAID-5 is a reasonable trade-off between speed and reliability. Of > course, that still requires backups because [All together now], “RAID is not > backup." > >> I realize there is no security (as with RAID-1), but I plan to do backups, >> so hopefully that will provide some level of security. > > If you backup a file that has a write error you end up with a bad backup of > that file. The issue with RAID0 especially with Macs isn that HFS+ is … well, > not good. The larger disks get and the more files we throw at it, the less > good it is. Yes, even with journaling. > >> The LaCie 5big comes as a 5-disk RAID-0 array (5 x 2-TB = 10-TB). For some >> reason, their thunderbolt 5big only provides software RAID via OS X Disk >> Utility. So my only other choice is RAID-1. I thought I might switch from >> a single 5-disk RAID-0 to a 3-disk RAID-0 (for Time Machine backups) and a >> 2-disk RAID-0 for something else (maybe even a different backup scheme). > > According to LaCie the 5big not only supports RAID5, but that is the default > configuration, although they also refer to RAID0 as the default. > > <http://www.lacie.com/support/faq/faq.htm?faqid=10607>
Thank you very much for your comments. I was worried about using RAID-0, and now I am even more worried! I agree that hard drives seem to go bad fairly quickly, and so that problem gets compounded with RAID-0. I really wanted RAID-5. As you say, it sounds like a good compromise between speed and reliability. Thanks for the link, but that must be an old web page. I have contacted LaCie tech support several times and they say that only RAID-0 and RAID-1 (and JBOD) are available in the *THUNDERBOLT* version of the 5big. There is a NAS version of the 5big, and there used to be a USB-3 version of the 5big (but now it's a 4big), and these support RAID-5 and RAID-10 (through hardware). But the current *THUNDERBOLT* 5big uses OSX Disk Utility, so we get software RAID-0 or RAID-1. I'm really thinking that I should send back the Thunderbolt 5big and perhaps get a USB-3 version or a NAS version. The whole reason I wanted the thunderbolt version was because I thought I would get a NEW Mac Pro, but I ended up getting a 2012 Mac Pro, so thunderbolt is of no use. I added a USB-3 card, so I could get the 4big, or if I just want it for backups, maybe I should just get a NAS and use ethernet. I have another two weeks in my 30-day return window, so perhaps I should return the thunderbolt 5big and get something else. Any suggestions will be greatly appreciated. Thanks, Gregg P.S. I briefly looked into a Drobo 5d, but I read some bad reviews that scared me off. _______________________________________________ MacOSX-talk mailing list [email protected] http://www.omnigroup.com/mailman/listinfo/macosx-talk
