Archived posting to the Leica Users Group, 2010/03/25
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Leo, As you say, and as for a missing person, the questions would be "when did he disappear and what was his name?" This is typical: "We need to restore a file on hermes. We need the file: /usr/users4/support/cacclmonth From any time before January 5th." Without having specific information one can list the files on a tape, or restore tape to disk and look on disk. Static data which is on many tapes or every tape would not require the "when" question. I have had to do a binary search through time intervals to attempt to find something. That is not fun. It depends on how valuable the data is and the amount of time one wants to spend looking. If data has no value, backup is unnecessary. There is also the question to consider: what if the disk or disk system fails? I have had supposedly ultra-reliable everything stored twice array systems loose everything. John Leo Wesson wrote: > I don't really know much about this, bit at my old corporate job they > did tape backup of the servers and they may as well not have done it. > It was impossible to get anything off the tape unless you knew the > filename and write date. There was no way, we were told, to search the > tape. > > Has that changed in tapeworld? > > Leo Wesson > photographer?videographer > leo at leowesson.com > 817?733?9157 > > On Mar 25, 2010, at 5:06 AM, Dennis <dennis at hale-pohaku.com> wrote: > >> Hi Spencer, >> >> I think we may want to put this over to the Imagestore list, but. >> >> At some point, say over 10TB, and growing, I think you are reaching a >> point of diminishing returns using disc drives for backup and/or >> archiving. Managing a lot of disc drives manually becomes a tedious >> and error prone task. This is where automation can be your friend. >> John's tape library is more than I would expect a photographer to need >> but I would want a library that accepts at least two drives in order >> to migrate data to the next generation media. Typically these >> libraries are attached to servers. I am not sure but expect that you >> can run them on a unix or windows system, not sure about Mac. >> >> It's likely that you will need a server to keep up with the >> performance of the drive. LTO 4 can write data at speed of up to 120 >> MB/s.I don't think windows desktop can serve up that data rate. The >> drive can stream at lower data rates but obviously the backup will >> take longer. >> >> The LTO format is very reliable. They are not designed to be consumer >> products, the typical customer is going to be a large corporation that >> expects and gets a reliable product. The media life that John quoted >> sounds like the spec to me. Once you write data to the tape you should >> never have to check it. If you want I can discuss the read after write >> that occurs in real time when data is written, the error correction >> that is part of the LTO specification, and, importantly the servo >> tracking that is important to ensuring data written can be read back >> on another drive. Keep in mind that the major drive manufactures are >> HP, IBM, and Quantum (Quantum acquired its seat as one of the >> technology providers of the LTO Consortium when Quantum bought >> Certance, a spin off from Seagate) >> >> Backup software is going to be selected from the library vendors list >> of qualified vendors. >> >> Goodnight, >> Dennis >> >> >> Spencer Cheng wrote: >>> John, (& Dennis), >>> >>> Suppose you are a working pro like Tina, Leo or Ted, or..., and you >>> have a gazillion digital photos, what would you buy for tape backups? >>> Assume that it has to work with a PC and a Mac, though not at the >>> same time. >>> >>> How reliable are these tapes? How frequently do they have to be >>> replaced? How often do the content have to checked? What S/W should >>> they use? Is there a recommended backup schedule? >>> >>> I've came across cases where the tape drive was flakey and the tape >>> was blank. I also seen tape drive s/w that generates hundreds of >>> (transient?) errors when I worked for a small company and we used >>> tapes for backups. >>> >>> More fodder for the wiki but I think this is useful information to >>> capture because once one data needs exceed 2TB, commodity NASes >>> becomes a bit of a dead end. Even my home brew NAS becomes less >>> useful once it gets to >3TB. Having a stack of NASes is no better >>> than a stack of external disks (or a very large stack of DVD-R). >>> >>> Regards, >>> Spencer >>> >>> On Mar 24, 2010, at 12:52, John Nebel wrote: >>> [...] >>> >>>> Relevant to the LUG: Given the high value of photographic images, >>>> and low cost of media and a PC internal tape drive, tape archiving >>>> is cost-effective. There can be many backup copies and tapes may be >>>> kept in multiple locations. >>>> >>>> Disk redundancy is essential, but one must do both. >>>> >>> >>> >>> _______________________________________________ >>> Leica Users Group. >>> See http://leica-users.org/mailman/listinfo/lug for more information >>> >>> >> >> _______________________________________________ >> Leica Users Group. >> See http://leica-users.org/mailman/listinfo/lug for more information > > _______________________________________________ > Leica Users Group. > See http://leica-users.org/mailman/listinfo/lug for more information