Archived posting to the Leica Users Group, 2010/03/24
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Dennis, "I think you mean your tape library must be able to read them all." Almost true as I am saving a standalone DLT3 drive rather than bothering with HVD interfaces in the library. Hasn't Quantum has given up on DLT? LTO5 is a joint effort with Quantum participating. 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. John Dennis wrote: > > > John Nebel wrote: >> Dennis, >> >> Yes, HP was bragging about T10 a while back, thanks for reminding me. >> >> The issue of multiple formats is an interesting one. We have DLT3, >> DLT4, SDLT1, SDLT2, and LTO4 and must be able to read them all. It >> wasn't too long ago that there were 9-track tapes in the archive. > I think you mean your tape library must be able to read them all. The > DLT & SDLT are Quantum's proprietary format, the cartridges don't work > in LTO drives. LTO is an open format and drives must pass an > interchangeability test to bear the LTO logo. Your tape library should > be able to migrate data from the DLT & SDLT media to LTO media. I would > think it is a goal to do that by some future date. Whether or not > Quantum wants you to migrate from SDLT to LTO is another question! > > I think when you need tape that LTO is the only choice due to the > multiple vendors that help keep prices down. I don't think anyone here > on the LUG has so much data they need tape, at this point. Perhaps if > Tina gets her 1.5 million film images scanned! > > Dennis >> >> LTO4 is probably a good choice for a PC at this point as the drives >> and media are pretty cheap. >> >> John >> >> Dennis wrote: >>> A big advantage of automation, tape libraries, is that with multiple >>> drives you can automate migration of data to newer format tapes. In >>> John's case he can ujpgrade some of the drives to LTO-5 or LTO-6 and >>> add the new higher capacity media and migrate data from the LTO-4 >>> media to newer media. When you have many terrabytes of data those >>> expensive tape drives start to look pretty desirable. >>> >>> John; the interface between the automation and the drives used to be >>> pretty simple with each automation vendor having their own protocols. >>> It has been replaced by a standardized protocol that is under the >>> INCITS T10 technical committee. If you want to take a look you can >>> download draft standards from the t10.org website. PM me if you do >>> and I'll guide you to the right spot(s). >>> >>> >>> John Nebel wrote: >>>> Spencer, >>>> >>>> LTO4 tapes are around $30/ea on ebay in lots of 20. The drives are >>>> $thousands, but one drive is infinite offline storage. >>>> >>>> John >>>> >>>> Spencer Cheng wrote: >>>>> Hi John, >>>>> >>>>> Very nice. The techie in me says "Cool. Can I borrow it?" :) >>>>> >>>>> I am not sure I want to know how much those LT04 tapes are. :)) >>>>> >>>>> My home built NAS cost about $1K including 5.5Tb of disk space. >>>>> Good enough for my purpose. Nowhere near as cool as yours though. >>>>> >>>>> Regards, >>>>> Spencer >>>>> >>>>> On Mar 22, 2010, at 20:22, John Nebel wrote: >>>>> >>>>>> Hi Spencer, >>>>>> >>>>>> Your post motivated me to photo part of the internals of a backup >>>>>> device, a robotic tape library with a petabyte capacity (600+ 1.6 >>>>>> terabyte tapes). >>>>>> >>>>>> http://www.ancientmoney.org/library.html >>>>>> >>>>>> If one has the space, time, and and a bit of knowledge, things >>>>>> like this can be acquired fairly inexpensively. I had installed a >>>>>> couple of LTO4 tape drives, and someone in Quantum service became >>>>>> upset and canceled a $20K/year maintenance contract - one is not >>>>>> allowed to work on their own equipment under their rules. >>>>>> Generally speaking, it is a reasonable position, however, not in >>>>>> every case. Quantum left me stranded with a broken hoist cable for >>>>>> the robotics platform, and I'd made the mistake of power-cycling >>>>>> the library and nothing would come online. The tape drive >>>>>> enclosures have electronic switches which only allow the drives to >>>>>> power up after the robotic diagnostics succeed. $10 for stainless >>>>>> steel aircraft cable (not for use in aircraft, of course) and $50 >>>>>> for cutting and swaging tools and it was back in operation. >>>>>> >>>>>> Quantum gave a credit for the prepaid maintenance which bought a >>>>>> pallet of tapes. Ultimately Quantum was apologetic and showed >>>>>> good integrity. >>>>>> >>>>>> I found a used library for $5.5K which works perfectly and >>>>>> provides the necessary backup for the backup device. >>>>>> >>>>>> In the process I looked into the library's controller and found >>>>>> its OS quite comforting, Linux. The OCP is a tiny flat screen >>>>>> xterm with a four button keyboard and the library runs Apache for >>>>>> its web interface. I think the interface between the robotics and >>>>>> the processor is serial with simple ascii commands. The interface >>>>>> between the tape drives and the outside is fibre channel through >>>>>> bridge cards. One talks to the Linux processor over ethernet, >>>>>> however, there is also a fibre channel card in the controller so >>>>>> that robotic commands may be sent via scsi over fc by the hosts. >>>>> >>>>> >>>>> _______________________________________________ >>>>> 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 >> >> _______________________________________________ >> 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