terryk@encore.com (Terence Kelleher) (09/11/90)
How do large systems typically deal with the problem of backups? I am trying to find answers for a 50-100 Gbyte disk system. Although 8mm and 4mm have the capacity to handle the amount of data efficiently, the transfer rates are quite slow, given the volume of data to move. Also, the reliability of the heilical scan devices is well established. 9-track tapes have the speed to handle the volume, but the number of tapes required and the need to change tapes so often make storage and operator involvement big issues. What other solutions exist for Unix systems? -- Terence Kelleher Encore Computer Corporation terryk@encore.com
nsoley@oracle.com (Norman Soley) (09/11/90)
I just got some marketing stuff in the mail today from epoch that talks
about using their boxes to back up large systems (100+ GB). In case you
don't know epoch makes Optical disk NFS server boxes (Yes I know they're
more than that but that's the basic idea).
Norman Soley - Systems Administrator - Oracle Corporation Canada
155 University Ave. Suite 400 Toronto, Ontario (416)-362-7953 X646
nsoley@cnseq1.oracle.com uunet!torsqnt!cnseq1!nsoley
"These opinions are mine, not the companies"yar@cs.su.oz (Ray Loyzaga) (09/11/90)
In article <12701@encore.Encore.COM> terryk@encore.com (Terence Kelleher) writes: > How do large systems typically deal with the problem of backups? I am > trying to find answers for a 50-100 Gbyte disk system. > > Although 8mm and 4mm have the capacity to handle the amount of data > efficiently, the transfer rates are quite slow, given the volume of > data to move. Also, the reliability of the heilical scan devices is > well established. > > 9-track tapes have the speed to handle the volume, but the number of > tapes required and the need to change tapes so often make storage and > operator involvement big issues. > > What other solutions exist for Unix systems? > -- > Terence Kelleher > Encore Computer Corporation > terryk@encore.com Talk to Sony and HP about WORM and magneto-optical disk systems. There is also an interesting system incorporated in the Plan-9 filesystem, the filesystem is implemented on a very large WORM (120Gb?), and disk/memory is a cache for it. You get a copy on write version of a file, which will eventually get onto the WORM. The larger optical jukeboxes will let you do unattended backups, but the disks are rather expensive. We will be getting a 20Gb "write many" jukebox which will be used for unattended backups and for an archival/retrieval system. The system will allow for online retrieval of quite recent material and when the jukebox is nearly full, the older platters can be stored away, much like tapes. The biggest reason why we are going this way is that most users are using disk to store data that they would be perfectly happy to put on a reliable system that will return the data in a timely fashion, they don't look at some files for years, but it gives them a cosy feeling to keep them around. If they could get them back from an archival system in a few minutes they won't need to keep in on our fast and expensive hard disks. These systems also have benefit for program/system development because it becomes a trivial matter to store a snapshot of a system under development without running into disk space limits. E.g. its nice to keep a copy of X11.3 around but it doesn't have to be on disk, and tape is too slow, so in a few tens of seconds you can access it on a jukebox system. My guess is that a lot of work will be going into these sorts of storage systems in the future. It is fast reaching the point in our department where we have more disk than we can comfortably manage and the growth in usage is being driven by the fact that we have given up trying. Nobody knows what they are keeping in their directories just in case they need it in the future.
pjg@acsu.buffalo.edu (Paul Graham) (09/12/90)
terryk@encore.com (Terence Kelleher) writes: |How do large systems typically deal with the problem of backups? I am |trying to find answers for a 50-100 Gbyte disk system. well we use 8mm. i don't have too awful a feeling about getting the data off a year later. epoch, qstar and some others are into optical jukeboxes. the epoch system is an automagic staging system that uses magnetic and optical disk with an 8mm tape. you turn it on and stuff migrates around of its own volition. neat -- pricey. general atomics has a variant of their mainframe system for unix. it uses a dedicated workstation with a fancy tape (maybe ampex) that holds 10-100 gig. or something like that. somebody (maybe legato) sells a smart network backup system. how smart? well everyone shouts at the tape at the same time and despite that the software keeps it straight (they say). one presumes the idea is to keep that 8mm streaming so you really can write 1G/hr/drive. we had a little chat about this at the anaheim usenix. (about 100 folks in a room for an hour). rob kolstad moderated and posted the outcome a bit ago. look (or ask) in comp.org.usenix. -- pjg@acsu.buffalo.edu / rutgers!ub!pjg / pjg@ubvms
fab@PacBell.COM (Fred Brewer) (09/12/90)
In article <1990Sep11.020003.4781@oracle.com> nsoley@oracle.UUCP (Norman Soley) writes: >I just got some marketing stuff in the mail today from epoch that talks >about using their boxes to back up large systems (100+ GB).... Also ask your AT&T sales rep about a thing called Comm Vault. Glossies make it look like the epoch system with the addition of hyperbole about connections to Datakit and StarLan. -- -- Fred Brewer Internet: fab@pacbell.com USnail: 2600 Camino Ramon, Room 1E150P mabell: (415) 867-6647 San Ramon, CA 94583
ghg@ecn.purdue.edu (George Goble) (09/13/90)
In article <12701@encore.Encore.COM> terryk@encore.com (Terence Kelleher) writes: >How do large systems typically deal with the problem of backups? I am >trying to find answers for a 50-100 Gbyte disk system. > >Although 8mm and 4mm have the capacity to handle the amount of data >efficiently, the transfer rates are quite slow, given the volume of >data to move. Also, the reliability of the heilical scan devices is >well established. > The Exabyte EXB-8500 8mm drive, due out in the near future, will do 30MB/min xfer, and 5GB on a P5-90 8mm tape. This compares to approx 2.5GB and 15 MB/min for the current EXB-8200. --ghg
merritt@iris613.gsfc.nasa.gov (John H Merritt) (09/13/90)
In article <1990Sep12.175324.23808@ecn.purdue.edu> ghg@ecn.purdue.edu (George Goble) writes: >In article <12701@encore.Encore.COM> terryk@encore.com (Terence Kelleher) writes: >>Although 8mm and 4mm have the capacity to handle the amount of data > >The Exabyte EXB-8500 8mm drive, due out in the near future, will do >30MB/min xfer, and 5GB on a P5-90 8mm tape. This compares to approx 2.5GB >and 15 MB/min for the current EXB-8200. In the August 6, 1990 issue of Unix Today, Cybernetics advertizes 8mm with 10.24GB at 60MB/min. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ John H. Merritt # Yesterday I knew nothing, Applied Research Corporation # Today I know that. merritt@iris613.gsfc.nasa.gov #
brtmac@matt.ksu.ksu.edu (Brett McCoy) (09/14/90)
In <3395@dftsrv.gsfc.nasa.gov> merritt@iris613.gsfc.nasa.gov (John H Merritt) writes: >In the August 6, 1990 issue of Unix Today, Cybernetics advertizes >8mm with 10.24GB at 60MB/min. That tape drive gets it's so called 10G from data compression. 10G is a maximum that you are going to get. That equates to a 4x compression, which you are not going to get very often. Mostly you will get 2x unless you have a lot of compressed files that you back up which you could wind up expanding when you try to compress it. You also have no way of determining beforehand how much data is actaully going to fit on the drive. Also, the data compression is an option to their normal drive. If I remeber right it adds over $1000 to the cost, which isn't one of the cheaper drives on the market in the first place. All in all, unless you are backing up mainly text with little binary code or compressed files, it isn't going to work real well. >~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ >John H. Merritt # Yesterday I knew nothing, >Applied Research Corporation # Today I know that. >merritt@iris613.gsfc.nasa.gov # -- Too bad the universe doesn't run in a segmented environment with protected memory. -- Wiz from "Wizards Bane" by Rick Cook Brett McCoy | Kansas State University brtmac@maverick.ksu.ksu.edu | UseNet news manager.
ghg@ecn.purdue.edu (George Goble) (09/14/90)
In article <3395@dftsrv.gsfc.nasa.gov> merritt@iris613.UUCP (John H Merritt) writes: > >In the August 6, 1990 issue of Unix Today, Cybernetics advertizes >8mm with 10.24GB at 60MB/min. Could it be two EXB-8500's in a common controller to look like one large drive? (with no compression). 50% compression on an EXB-8500 would also give 10GB 60MB/min. I believe the tape media (low grade 8mm sony tape) is good for 10 GB, if anybody can build a drive to write it. The 8500 does not increase the linear density over the 8200, it just writes tracks (stripes) inbetween the existing ones.., so it has double the number of tracks per inch, but same density. the 2X xfer rate comes from the fact that tracks are written two at once now (5 heads, on servo, two write, two read). Imagine what 50% compression would do on that drive (20 GB, 120MB/min). --ghg
doc@tera.com (Dan Cummings) (09/20/90)
In <5400@ptsfa.PacBell.COM> fab@PacBell.COM (Fred Brewer) writes: >In article <1990Sep11.020003.4781@oracle.com> nsoley@oracle.UUCP (Norman Soley) writes: >>I just got some marketing stuff in the mail today from epoch that talks >>about using their boxes to back up large systems (100+ GB).... >Also ask your AT&T sales rep about a thing called Comm Vault. Glossies >make it look like the epoch system with the addition of hyperbole about >connections to Datakit and StarLan. You may also want to call the folks at DISCOS. They have a product called UniTree which is designed for large Unix environments. They can be reached at (619)455-3751 and are located in San Diego, CA. Dan Cummings