Bob Hetzel wrote: > The reality is that if you really need reliable data for 10 years you're > probably stuck with technology like paper, optical media (choose wisely > as many of these formats are gone too), or online hard drive space that > you'll be continually checking and carrying along with each upgrade (and > backing up with all your regular fulls). All have their own major > drawbacks. The benefit to online hard drive space is that new data > needs grow so fast that in many cases it's not that much more expensive > to keep the old stuff around--for instance... 20 years ago 100GB of data > was not available in one storage system. 10 years ago it was a lot but > quite pricey. Now it's about the smallest hard drive you can buy new. > > The odds that you can locate a working tape drive of any current (2007 > hardware) type and adapters to plug it into 10 years from now (2017 > hardware) aren't good the way things are moving. Not only will you have > to worry about hardware--is PCI still going to go the way of the ISA bus > by then?--but drivers for old adapters on the OS after the next OS are > quite possibly going to be a problem--there's tons of useless adapters > out there now where manufacturers went out of business before updating > their NT 4.0 drivers to work with XP, Server 2000, and Server 2003, so > even if you save both the tape drive and the adapter who's to say the > adapter will have a spot to plug it in and a driver you can load. > > With regard to 30 years I can almost guarantee problems with just about > any electronic removable media. While it's true that you can probably > find a 9-track mainframe style tape reader to read 30 year old data > tapes on many current computer systems, the market does not seem to be > maintaining that trend for the current storage stuff--things are moving > just too fast. That's been driven by IBM's mainframe dominance over the > last 30 years--corporations have been migrating off IBM mainframe > hardware right and left in favor of hardware from companies that may or > may not still be in existence 10 years from now. > > In summary... backup software is extremely important for disaster > recovery but should not be considered for long term (5+ years, possibly > even less depending on what you need it for) storage needs in my humble > opinion. > > >> Message: 22 Date: Mon, 24 Sep 2007 08:06:29 -0400 From: "John Drescher" >> <[EMAIL PROTECTED]> >> >> >>>> but cheap hard drive keep your data safe only for 3 - 4 years for >>>> sure (maybe longer) and some tapes (DLT, LTO) are specified to hold your >>>> data for 15 - 30 Years (if the tape is not constantly in use, so for >>>> archiving purposes). >>>> >> On top of that I have several other reasons why tape is better for >> backups. We have 10TB of data online (linux software raid 5 and 6) >> which represents between 1/2 and 2/3 of our data but we do not in any >> way consider this as a backup. What happens if the file system >> corrupts (I have seen this happen) and 1/2 of your data is lost? Hard >> drives use power and require extras (servers/cages) that make the cost >> of them a lot more than the price of a single drive. And they do not >> scale anywhere near as well as tape. And you have to replace them >> every 3 to 5 years or fear that you will loose your data. To avoid >> some of these problems you could store the drives on a shelf (in a >> temp / humidity controlled environment), however there is a big risk >> here that the drive will not spin when you install it 10 years down >> the line making the data on the disk very expensive to recover.
All of which means that any really serious long term backup and archive strategy becomes fairly complex and needs some real planning and ongoing attention. You need to have plans for checking the readability of your archival media regularly, plans for redundancy in your archival storage, and plans for migrating archives to newer media as the older media starts to become risky or unavailable. Unfortunately, few think in these terms. The monks of the middle ages copied and preserved books for many hundreds of years. Librarians think in terms of long term archives, rare book collections, etc. Now, in the digital age, Libraries can't afford to maintain their extensive periodical collections. It becomes the responsibility of commercial publishing houses to maintain the digital archives, and Libraries pay subscriptions for access. If a publishing house goes out of business, we no longer have the widely distributed redundant paper archives in Libraries all over the country or world. In the raging free market economy in the U.S., businesses come and go. Departments and staff in large corporations come and go. The 5 year business plan is thought to be thinking way ahead. Sorry, can't afford wasting money worrying about what might happen after that. If we can just churn enough business and make enough money, then that will inherently solve whatever problems we might face then. In the academic world there are increasing quantities of digital data that can't be reasonably reproduced on paper anymore. The day of the black lab book is gone. We have several labs doing research in DNA sequencing and evolution. They each generate hundreds of gigabytes of data a semester. They are debating what to keep and what to throw, or whether they should archive and keep it all. Some represents the data behind analyses that are in published papers. Oh, yeah, I do use tapes. I have a 6 week rotation of AIT5 tapes as well as end of semester archive tapes that will be kept at least 2 years and possibly indefinitely. We also have RAID and disk to disk copying for immediate access and redundancy. Many of the labs use external fire wire drives for backups as well as putting data on the servers where it ends up on my AIT5 tapes. And, . . . I wouldn't believe manufacturers claims for reliability or longevity of their media. See the item above about 5 year business plans. I've also worked with marketing people. Aside from an inherent conflict of interest (they get reviewed and retained on how well they sell the product, so why would you believe what they say about the product), I simply don't trust them. Too many promises are made to make a sale and then end up breaking the backs of the technical staff or even ultimately the company. We need to judge media by real experience in the community of users, or by *independent* technical analysis (not paid for by the vendor). Of those two, community experience is far easier to come by. I've seen or heard of a fair number of instances where RAID arrays made up of cheap SATA drives have experienced multiple drive failures resulting in complete loss of data. We've all heard of problems with optical media. As stated above, research and choose carefully. Note that there is a big difference between stamped CDs and either CDR or CDRW (and now the DVD variants of all of those). While I might believe something about longevity of stamped CDs, I think the others got a free marketing ride on the ignorance about the difference (and took advantage of it). On the tape side, there are those of us who have the experience of the reliability and longevity of mainframe 9 track reel to reel tapes, having read them back after more than 10 years. And, you can actually still buy a 9 track tape drive for what we now call servers to get back the data that was archived by mainframes. Lots of issues here to make the life of the techie complicated. --------------- Chris Hoogendyk - O__ ---- Systems Administrator c/ /'_ --- Biology & Geology Departments (*) \(*) -- 140 Morrill Science Center ~~~~~~~~~~ - University of Massachusetts, Amherst <[EMAIL PROTECTED]> --------------- Erdös 4 ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2005. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Bacula-users mailing list Bacula-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bacula-users
