Recently Jana Reiste of the Professional
Women's Fellowship in Seattle asked a question on the list about using
the backukp copy she keeps on a zip disk. The discussion moved in the
direction of backup procedures and eventually included 25 messages by
10 different people. In response to requests by a couple of people, I
have edited the thread into the summary below. This will get posted to
the ebase FAQ sometime soon. Many thanks to those who contributed to
this thread.
Some of the hazards mentioned below will
seem obscure, and worrying about them paranoid, but paranoia is
what backups are all about. Pretty much every week we see a post on
the board here about someone who has suffered file damage without
adequate backup. Zip disks are about $15, cds even less expensive,
cheap insurance for a function that is probably pretty important to
your organization.
As you read the tips below, keep in mind
that it's important to make the backup procedure easy and
understandable by the people who need to do it, or it will eventually
be ignored.
* Back up your ebase data by making a copy of all 29 data files in the ebase set (everything named xxxx_.103, not just the ebase.103 file).
A backup of ebase requires making a copy of all 29 active data files. These all have the suffix .103 (or .100, or .102, depending on the version.) and are located in the same directory. It's easiest to copy the entire directory. These files reference each other with scripts, calculations and relationships. Ebase won't function correctly or give you accurate information unless all 29 files are current.
* Make your backup copy on a different disk than your working copy (a removable disk like a zip or cd, for example) to avoid losing both the working files and the backup if the disk fails.
If you have a backup on the same disk as your main copy it will protect you only in the case of a file corruption such as FileMaker crashing. If the drive with your current ebase files fails, you lose both the current copy and your backup. In addition, if two sets of data files are accessible, FileMaker can sometimes get confused about which set it's supposed to work with. As a general rule, only one set of ebase data files should be on your hard drive at a time. If you need to keep a temporary set on your hard drive, compress it with an archive utility like Stuffit (Mac) or Winzip (Windows).
* Take the backup disk off site to insure against loss of the files due to physical damage such as fire or theft.
In addition to disk failure and file corruption, backups need to protect against physical damage such as fire, flood, and theft. If your office burns both the current copy and any onsite backups are gone.
* Use more than one backup disk, so you don't have to put your only backup in the computer to make a new backup.
When you are making a backup, both the
current version and your backup are in the computer at the same time.
The system is reading your current version and copying it to your
backup disk, overwriting the previous backup. If your computer crashes
or you have a power failure while both copies of a file are open, it's
possible to leave both copies in what is euphemistically called
"an undefined state", i.e., toast. Unless you have other
copies, you have no remaining backup of your data files.
* Keep a backup copy for several weeks. Problems can sometimes lurk for days or weeks before someone notices them, so you need to be able to restore from backups made days or even weeks previously.
Ebase is a pretty complex system, consisting of 29 interrelated files. Unless you exercise all the functions every day, it would be possible to damage one of the files and not notice it right away. If you are using only a few backup disks, rotating them daily, by the time you notice the problem you could have overwritten your backup copy with a copy of the damaged file. For example, something happens to your payments file on Monday. You do address corrections and send email Tuesday and Wednesday, but don't post any payments. Thursday you get a handful of checks in the mail and attempt to post them but FileMaker says your payments file is damaged. Monday night, and again Tuesday and Wednesday, you copied the damaged payments file to your backup zip disk along with the rest of the file set, and now you have no undamaged copy of the payments file.
If you back up to recordable cds, it's pretty easy to keep multiple levels of backups. Make a backup, take it off site and file it. You never erase a cd, so if you need to restore from a last month's backup, it's there in the files. A cd recorder is a little more complicated to use than a zip drive, but it's permanent. See below for details on cd recorders and how to use them to back up.
With zip disks it's a little more complicated. Zip disks are more expensive than cds (around $10) and erasable, so they get re-used. The key is to adopt a protocol that keeps a backup available for several weeks before you erase the disk and copy a new backup onto the disk. Use two stacks of disks - a daily set and a weekly set. Monday, backup to one of the daily zip disks and take the disk off site. Tuesday backup to a different daily disk and take it off site. Wednesday and Thursday back up to your third and fourth daily disks. At the end of the week back up to one of the weekly disks. Next week repeat the cycle with your daily disks, and at the end of the week, use a new disk for the 2nd weekly backup. Repeat for as many weekly disks as you can afford. If you find a problem within a few days, you can restore from one of the daily disks. If it goes back farther than that, try the weekly disks until you find a good file set.
If you happen to have both a cd recorder and a zip drive, you can mix the two methods. Do daily backups to a zip disk (easy and quick) with weekly backups to a cd (slightly more complicated but permanent).
* General notes
If you keep several backup copies on a single cd, make folders for them using the date of the backup in the name of the folder so you and the computer can tell them apart. It's a good idea to compress your backup copies using an archive utility like Stuffit (Mac) or WinZip (Windows). Compressing the backup copies takes less space on the drive, and keeps all the files in the ebase file set in one package.
* Using a cd recorder for backup
The cd-rom drive in most computers is read-only. To record to a blank cd, you need a special cd recorder, available from office supply and computer stores for $200 - $300. Blank cds are very inexpensive, about 50 cents. The main advantages are that the disks are inexpensive, and it's an optical storage method, inherently more stable than magnetic media like zip disks. A cd will hold 600Mb of data, anywhere from one to several complete backups, depending on the size of your database. Making backup copies to a cd is a little more complicated than copying to another type of drive. You need to use the special software which comes with the drive to open and close the disk, and possibly to make the copies. On Windows, the copies stored on the cd are marked read-only, and this has to be reversed on every file when restoring a damaged file from the cd. It's not difficult, but it does require additional steps when compared to using a zip disk.
* Using a zip disk for backup.
Zip drives are less expensive than a cd recorder drive (about $100) but the disks are more expensive than blank cds (about $10) and hold less data, about 100Mb. Using a zip disk for backup is simpler than a cd recorders. Backing up involves only copying the ebase directory to the zip disk. Reverse the procedure to restore from a backup. Zip disks are erasable and are commonly re-used periodically to store a more recent backup copy. Follow the procedure above to insure you keep some backup copies for at least a period of weeks.
* Back up other important files also.
Of course, ebase data is not the only important information in your office. Accounting data, budgets, letters, reports, employee files, etc., are all important and should be backed up with the same attention to security as your ebase files. If the material you want to back up totals more than the 600Mb a cd will hold, or if you need to back up files from several computers, you'll need to take the next step: specialized backup software and a tape drive. Tape is magnetic, re-usable media like zip disks, but of vastly greater capacity. You should set up the protocol outlined above for zip disks, using daily and weekly tapes. The backup software bundled with the tape drive can be instructed to make automatic backups after hours. All you'll have to do is put a different tape in the drive every day. A tape backup system will cost at least several hundred dollars, but that's still way less than the cost of manually restoring lost data.
--
--
Dave Shaw H4 Consulting
tel: 206-954-7526 fax: 206-625-1338
------------------ --
Dave Shaw H4 Consulting
tel: 206-954-7526 fax: 206-625-1338
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