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#21
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In article ,
Ron Reaugh wrote: best of all is in a granite mine on a different continent....well no best is in quantum entangled storage in another galaxyg. Your quantum entangled storage in another galaxy is no safer that wherever you have the nearside qubits stored. There is no magic bullet, not even if you invoke Arthur C. Clarke magic. -- I've seen things you people can't imagine. Chimneysweeps on fire over the roofs of London. I've watched kite-strings glitter in the sun at Hyde Park Gate. All these things will be lost in time, like chalk-paintings in the rain. `-_-' Time for your nap. | Peter da Silva | Har du kramat din varg, idag? 'U` |
#22
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"mschlack" wrote in message om... -snip One thing to clarify: do you have both restore and archive needs? Restore would be to rebuild after a disaster or after losing or corrupting specific files. Archive would be for long term retention -- rarely used data that's taking up space otherwise but would need to be occasionally mounted at some future point (like parts drawings for obsolete products). If you're truly archiving, then tape probably is a must (or optical), since the reliability of data that's never read on disk drives can't be assumed for many years (those little old bits can flip on you). SDLT is a solid choice, in any event. Tapes are NOT for long term storage. Only some opticals have been legally approved. |
#23
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In article ,
Ron Reaugh wrote: Tapes are NOT for long term storage. Only some opticals have been legally approved. That depends on your application and environment, legal requirements may not be a factor. We had 3480/3490 tapes that stored data in our archive that had very few read errors after 15 years of storage and use. Of course, they were kept in the climate controlled computer room for their entire life time. It is common to be able to read 1/2" reel-to-reel tapes that are 40 years old without too many problems as long they were stored in reasonable climate conditions. Now, however, with the increasing recording density of recent tape media formats, it may not be possible to get that kind of lifetime. Oozing of data to newer tape (or other storage) technologies may be necessary after 5-8 years. Personally, I'd prefer to trust linear recording formats over helical scan formats any day. NCAR has an archive that is approaching 2 PB (petabytes), all of it on tape. I suspect there are organizations with much more data on tape. -- Craig Ruff NCAR (303) 497-1211 P.O. Box 3000 Boulder, CO 80307 |
#24
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In comp.sys.ibm.pc.hardware.storage Craig Ruff wrote:
In article , Ron Reaugh wrote: Tapes are NOT for long term storage. Only some opticals have been legally approved. That depends on your application and environment, legal requirements may not be a factor. We had 3480/3490 tapes that stored data in our archive that had very few read errors after 15 years of storage and use. Of course, they were kept in the climate controlled computer room for their entire life time. It is common to be able to read 1/2" reel-to-reel tapes that are 40 years old without too many problems as long they were stored in reasonable climate conditions. Now, however, with the increasing recording density of recent tape media formats, it may not be possible to get that kind of lifetime. Oozing of data to newer tape (or other storage) technologies may be necessary after 5-8 years. Personally, I'd prefer to trust linear recording formats over helical scan formats any day. NCAR has an archive that is approaching 2 PB (petabytes), all of it on tape. I suspect there are organizations with much more data on tape. Yes, in the early 90's the large company I worked for converted all of the hundreds or thousands of history tapes from reel to 3480 cartridge. IIRC all of the tapes, some 10 years old or more, were readable. We also performed a yearly disaster recovery test wherein we would go to a recovery center for 3 days and restore our IBM mainframe system from 3480's. We'd have our entire disaster library shipped across the state by truck to the recovery site. We never had any problems reading the backup tapes. Jerry |
#25
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Keep working there as long as you get the personal advancement you
need to stay happy. Wait for them to have a problem that the current backup solution cannot handle. Make sure you have your own way to recover everything. When disaster occurs quit... Offer to come back as a consultant at 3X your current pay rate to oslve their problem. |
#26
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On Tue, 22 Jun 2004 20:33:16 GMT, "Ron Reaugh"
wrote: Tapes are NOT for long term storage. Only some opticals have been legally approved. Legally approved by what organizations? Here are the methods of archival storage for a couple of the US's largest data gathers: Library of Congress National Oceanographic Data Center Of course, the Census Bureau has learned their lesson the hard way. Due to the high costs of migrating digital data over time they are now moving back to microfilm: http://www.fcw.com/fcw/articles/2001/0108/web-census-01-09-01.asp --- Here is the solution used by the US Library of Congress: http://www.dlib.org/dlib/may96/loc/05c-arms.html#preserve "To address the estimated need for 50 terabytes of managed storage by the year 2000, the Library will be installing a commercial hierarchical storage management system over the coming months. Storage management software will transfer files automatically between high- performance disk drives and less expensive storage media from which retrieval will take longer. Typically, the location is based on time since last access, but more complex rules can be enforced. Since the highest resolution images will be accessed only occasionally, they will usually be resident on the slower medium. The allocation is transparent to applications accessing the files; "stub" files left in the logical file hierarchy point to the physical location of files that have been relegated to another "layer" of storage. For its second layer of storage, the Library has chosen high capacity magnetic tape cartridges under robotic control. The tape unit (IBM's 3494 Tape Library Dataserver) has been installed and is already in use for regular backup and restore operations (associated with any computer system). Generation (and periodic regeneration) of archival copies of collections on tape cartridges is also possible for preservation of the digital materials. The hierarchical storage management software (ADSM from IBM) will be installed on individual computers over the next few months, in conjunction with system upgrades. " -- Here is the method used by the US National Oceanographic Data Center http://www.nodc.noaa.gov/General/NODC-About/archive_access.html "NODC currently operates a number of Digital Linear Tape (DLT) and IBM 3590 tape media systems for backup and archive and for off-line storage. NODC operates automated systems to perform regular virus scans of data in storage both during ingest and periodically thereafter, and also to generate cryptographic checksums of all digital archive data so that its integrity can be verified at any time. This allows for a high degree of confidence that any data corruption due to media failure or accidental or intentional destruction can be easily detected so data can be recovered from off-line backup media. It also allows for data migration across future generations of storage media and systems with a high degree of confidence in the inherent data integrity. NODC also operates a number of high-capacity RAID (Redundant Array of Inexpensive Disks) disk storage systems to support data ingest, working storage, online products and database search and retrieval systems. Tape jukebox systems are maintained at NODC to provide automated and manual backup facilities supporting the NODC workstations and servers as well as near-line mass storage jukeboxes (the backup copy results in a third copy of the original data). These systems currently use DLT technology and run under the control of Legato Networker backup software. Tape media systems are maintained to support data retrieval from legacy tape formats such as 9-track, and to copy data to IBM 3590 tape media for offsite, deep-storage archive. Other tape systems are provided for backup and restoration of database and critical data and information servers." -- And the method for the |
#27
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On Wed, 23 Jun 2004 19:11:33 -0700, Scott wrote:
Keep working there as long as you get the personal advancement you need to stay happy. Wait for them to have a problem that the current backup solution cannot handle. Make sure you have your own way to recover everything. When disaster occurs quit... Offer to come back as a consultant at 3X your current pay rate to oslve their problem. Hmm, that's good advice. ~F |
#28
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"Scott" wrote in message ... On Tue, 22 Jun 2004 20:33:16 GMT, "Ron Reaugh" wrote: Tapes are NOT for long term storage. Only some opticals have been legally approved. Legally approved by what organizations? Tax data etc....the last time I checked only some kinds of optical were approved. |
#29
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On Thu, 24 Jun 2004 20:45:39 GMT, "Ron Reaugh"
wrote: "Scott" wrote in message .. . On Tue, 22 Jun 2004 20:33:16 GMT, "Ron Reaugh" wrote: Tapes are NOT for long term storage. Only some opticals have been legally approved. Legally approved by what organizations? Tax data etc....the last time I checked only some kinds of optical were approved. Correct. For Europe there are only two systems (both optical) that are approved for tax data. That means, that only those systems are allowed when that system is the ONLY place where the data is stored. If the data is ALSO still stored on harddisk, then a tape backup is enough. Suprisingly almost nobody seems to know about these regulations. There are lots of financial organizations that use archive media which are not legally approved. (like CDROM) Marc |
#30
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On Sat, 19 Jun 2004 21:14:47 GMT, "Ron Reaugh"
wrote: [ Snip ] In short, I need some type of recommendation, in writing, in some type of white paper, from some type of credible sources, that SDLT tape backup drives, at least for the purpose of long term archiving Tapes have NEVER been considered a viable "long term archiving" medium. Neither, though, has anything else, except for paper. Tape is, and has been proven to be, better than most things, and particularly better than disk whose failure modes tend to result in massive data inaccessibility more often than those of tape. However, this issue is not tape-vs-anything else, it's on-line and on-site vs. off-line and off-site. [ Snip ] Reliability is always the sum of all such factors and any backup strategy should look more towards the least common denominator...Murphy....an automatic corrollary to Murphiy's law is that tapes are unrelaible. The proof of that is the incredible cycle strategies that have developed over the years for tape backups. That comes from the fact that too frequently the tape isn't usable for any one of a number of reasons. Substitute "backup medium" for tape and there would be something useful in the above... Malc. |
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