The Tape Debate
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The Tape Debate
Get rid of tape? I don't think so. But that's what Synopsys is considering with the installation of new storage appliances and software from Data Domain, EMC, and Network Appliance.
Disclosure: I have friends that work for Network Appliance, so I may take gratuitious shots at them for the sake of humor
While you might look forward to having Jennifer come install a Network Appliance SAN at your site, it might not be worth giving up your tape system. After all, if there's a fire near your building and the fire department comes, you might experience delays as she and the rest of the females nearby stop working stand in awe of those strong fireman. How do you back up your data when a 2TB appliance is sitting half installed and you've already arranged for the removal of your tape system to the local eBay retailer!?!?!?!
And even if you get the appliance installed with Data Domain's de-dupeing software and get a 20:1 compression, how do you get those bits back when you need a restore. Bringing back every 20th bit on a SQL Server database just isn't practical. 🙂
All fun aside, archiving data requires lots of space. And coming up with a scheme to avoid every day fo the last 7 years is possible, but not easy to manage necessarily. You might get by with every day of the last week, end of months, and then end of years, but who knows. Plus there's always the chance of an audit for some snapshot on the day before or after a close of month or quarter.
I do think that using disk storage can help reduce your tape needs, but over time, especially with more legal requirements to keep data records for long periods of time, a tape system is still probably an essential tool for most companies.
Steve Jones
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Who is this Jennifer, and does she have a swimsuit layout?
I think it would be prudent to keep your tape system around until media such as DVDs get enough capacity to be worth the while.
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I don't think we will see tape go away any time soon. How do you take data offsite if you don't have tape? I do think disk can help improve the performance of backups, by copying data to different disks, then to tape, you can shrink the backup window for any given data store.
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Two words here: OFF SITE.
That wonderful SAN in your data center can burn to a crisp just like the rest of the building. I have had too many clients involved in disasters to not have learned the lesson. None were involved in 9-11 but that was a wakeup call too.
Three more words: TEST YOUR BACKUP.
Backups are no damn good if you can't restore them. I recovered data from a client with a faulty tape system. All the bytes were there, just not in the right files.
Days on end were spent trying to piece that back together. I even ran across a tape system that, when verifying the backup only ensured that the tape was readable. I asked the vendor if there was a way to compare the data on the tape to the data on the drive. The respose was, "Why would you want to do that?" We did not buy that system. Guess why.'Nuff preaching.
ATBCharles Kincaid
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Jennifer's a friend who works for NetApp.
She's probably got a swimsuit, but I don't think she'd do a layout for us
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ATBCharles Kincaid
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I have two Data Domain DDR460s at two sites with replication turned on between them. I am keeping one year worth of data on disk. A full backup is approximately 2TB of data. I have not had a problem with restores (yet). I may archive a full backup to tape at year end, but for the most part I am tapeless and loving it!
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Among the other duties of life in the electronic fast lane, I'm the monkey that feeds the tapes into the machines.
I have also experienced reading log after log of successful backups with a redundant verification of what's on the tape only to find it lied when it came time to recover.
I long ago set up backups to first be copied to another drive and then to tape for both redundancy and speed of restores.But, I am also now looking at a backup scheme using USB drives (becoming more inexpensive every day) for each server and actually swapping those out on some sort of schedule instead of tapes. Coupled with offsite backups either across the network or Internet, tapes just might be on the verge of being replaced.
And the monkey can find something else to do like read SQL forums...
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We got rid of tape several months ago, utilizing removable 250gb hard-drives in a 4 drive external SATA II tower and a separate NAS.
We use imaging software to get a fresh image of each server on the weekend, then incrementals throughout the week at one hour intervals. The images are created on a 1.5TB NAS device which can hold mutliple weeks of data. A copy of the base (full) images are copied to one of the removable drives, its popped out and sent offsite (weekly). The hourly incrementals are created on the NAS with a copy moved to another one of the removable drives and transmitted electronically offsite on a daily basis.
In case of a disaster, if we can grab the current drive on the way out the door, we stand to lose no more than the current hours worth of data. If not, then we may be out 2hrs depending if the offsite synch has completed. For normal backup functionality we have hourly snapshots of our data for file restoration which takes only a few minutes (<5) with the hard drives vs considerably longer with the average tape restore.
Granted our storage needs are modest by most standards, but with the size of SATA drives now over 750GB, its a good solution for many.
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Tim that's a really interesting solution. I've love to hear more in an article as I'm sure many would. How much data are you talking about for a full backup?
Dave, you mention 2TB of data for a full backup, how much space is needed for a year's worth of data? Is it 700TB?
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We image 6 servers - the total compressed data of the base images is (currently) about 175GB.
The incrementals during the week take about 6 GB. That it is not all new data, (we add about 500MB a week), just the way the imaging software creates the incrementals, so our weekly base images only grow about 500MB a week (compressed).
The process is fully automated (using batch files to purge/move prior weeks on the NAS) and a small .Net app that copies from the NAS to the removable SATA device. All we have to do is pop-out the removable drive and send it offsite.
As for an article - there's not much to it, but I will be glad to write something up and send it to you.
Another benefit of imaging is migration. We have used images to migrate hardware- moving a server from a 5 year old Dell PowerEdge using SCSI to a new box that used SATA. Imaging has until recently, been restricted to restoring the OS to similar hardware, but the vendors have it working so you can push it to totally different hardware. The time and effort saved vs a full-reinstallation is huge.
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