Disaster Recovery

Pros and cons of replication and tape for data protection

IT pro Rick Vanover considers the decision of data protection exclusively via replication or by relying on the venerable tape device for small and medium businesses.

Offloading to tape is a data protection strategy that does its purpose well, but can surely be made better in today’s IT landscape. There are good things about tape, such as its ease of transport, low cost, and the relative safety of accidental deletion. On the other hand, the critiques of tape are in no shortage. Tape can have reliability errors that mysteriously only seem to happen on a restore as well as occasionally falling off of a truck. For the small and medium business, these are important factors as alternatives are limited.

Administrators today have a viable alternative in using replication technologies to another site to meet a fundamental requirement of storing backups off-site. This site can be another location within the organization accessible via a private network, WAN or Intranet. This site could also be a cloud storage provider for data protection, which I still think can be the first way organizations migrate to the external or public cloud. I want to keep cloud out of this discussion and focus on replication and tape for migrating protected data off-site.

Replication technologies can be done a number of ways. Take for example a common configuration that backs up systems and data to disk first and then offloads the retained data to tape. The system that performs the backup has an archive of the systems it is protecting; in many backup software products, this is the second tier of protection. The third tier would be the offload to tape. If the backup system and its associated second tier storage are replicated to another system at another location within your organization, are your off-site requirements met? These replication techniques can include any of the following:

  1. Protection tool software This replication can protect a physical or virtual machine via a software tool such as Acronis, Novell PlateSpin Protect, DoubleTake, Symantec Backup Exec System Recovery, Veeam, and others to a storage resource at another location on your network. These tools can continually create an image or update on a specified interval.
  2. Storage-based replication Many SAN products now include the ability to replicate LUNs from one storage controller to the other.
  3. Management software Scheduled tasks to clone a system (such as a virtual machine) to another location in your organization.

With these options, there is one crucial caveat. If a software or user error deletes data or other important content on the source, is it replicated to the protected site? Tape can have an advantage here by being removed from continuous I/O.

Replication technologies would propagate the deletion through all protection tiers if they are real time. The only way a protection policy can really be successful with replication is to have a schedule to accommodate for accidental deletion or additional tiers of protection that provide a point-in-time recovery within the tools in use.

I’m not exactly a fan of tape, yet there are many considerations to going to replication-only for off-site data protection. What are your thoughts on this transition and how your requirements apply?

About

Rick Vanover is a software strategy specialist for Veeam Software, based in Columbus, Ohio. Rick has years of IT experience and focuses on virtualization, Windows-based server administration, and system hardware.

43 comments
mickforegan
mickforegan

If you backup over the Internet to a 3rd party the data is usually encrypted for security purposes. It is vital to keep a copy of the encryption key off-site since without this it would be impossible to restore your data making the backup virtually useless.

calbrit01
calbrit01

Surprised D2D wasnt on this dicussion of options mutes any downside noted in the article bar cost.

dwdino
dwdino

What about those that mange 500+ servers with terabytes of E-mail and SQL data?

SeasonedsysDBA
SeasonedsysDBA

What kind of recovery? HW failure. Software failure. Late discovery corruption. User regret. In terms of cost, how much data can the business lose? None. 1 hour. 1 day. (Can the lost data be recaptured?) In terms of cost, how long can the business be without the data/system? Can it be manually restored and it at what cost (time/people)? Okay, based on the cost of a data/system loss to the business, NOW design the ENTIRE backup/recovery solution to meet your business' recovery requirements. For the data it could be tape, replication (to what degree?), or both. BTW, don't forget to factor in the time it will take to restore any required HW (and what is your HW recovery solution?)

jacobssnow
jacobssnow

I use a mixture. Each site has an inexpensive NAS device and an AD server. The NAS backs up to the server nightly, and the server backs up to a large NAS in the corporate office. This happens daily. Shadow copies are kept (for accidental deletions, etc...)on the two local devices. The large corporate office NAS is backed up to tape using a Grandfather/Father/Son incremental scenario and we store a monthly tape permanantly for SOX and historical purposes. This allows for very fast recovery, redundancy (in case a NAS crashes, the AD server can quickly take over the file server duties), and since we are using inexpensive NAS devices and AIT tapes - low cost overall.

Vandy-SJ
Vandy-SJ

Recently I installed a new RDX hard drive-based removable storage system, using the same number of drive cartridges as the previous tape cartridges. So far so good. Advantages: very fast backups (usually 6x faster backup and verify jobs), RDX cartridges life expectancy is greater than 5 years (vs. tape refresh cycles of approximately 1 year), far more capacity options (160GB, 320GB, 500GB, etc), similar cartridge size to tape cartridges, drive cartridges more reliable than tape in retaining data, no need to clean tape heads, and compatible with most current backup software that support disk-to-disk backup (Symantec Backup Exec, CA ARCserve, etc.). RDX systems are available from OEMs like HP, as well as other vendors. RDX cartridges use (internally) 2.5-inch SATA hard drives, and the cartridges are easily inserted/removed from a 'base unit' that is either a desktop USB base unit, or a 5.25-inch slot internal (mounted in server slot) USB base unit - a direct replacement for a SCSI or USB attached tape drive. The 'backup window' to backup and verify two servers, including a 30GB database application and data, went from 6 hours to 1 hour. The owners now offsite store daily disk cartridges instead of tape cartridges. Disadvantages: initial cost for RDX system and cartridges; however, over the life of the RDX compared to the cost of tape, RDX is faster, more reliable, and has greater capacity and shelf life. For small and midsize business, this is a nice solution for backup media.

AV .
AV .

Tape has always worked reliably for me in the past. It's cost effective too. Some gotchas I've experienced with our tape systems lately though: There is too much data to backup nightly and you have to use incremental backups (restores are complicated). For full backups, the data no longer fits on two tapes and there is no autoloader. We already have 2 backup units and would have to purchase a third one. My house is full of backup tapes. Everyday I carry some of them back and forth to work. I do offsite a few to a climate-controlled archive facility, but it really isn't what I'd call an effective disaster recovery solution. I am looking at replacing the tape backup units with a combination of replication/cloud. Its more expensive than tape, but would provide a real disaster recovery solution because the data would be located at a facility in a different state. If there was a disaster, we could be up and running in a shorter period of time than using tape. Its going to take some getting used to for me to ditch my backup tapes, but I think I'm going to have to. AV

Dutch2005
Dutch2005

offiste NAS works for us, its connected though fiber...

mpala007
mpala007

Users delete stuff and don't notice immediately or discover it a week or two later. I have done dozens of tape restores with no problem. One must always archive and rotate new tapes in and keep the heads clean. After full backups, the tape must be verified. Replication is fine but periodic snapshots must be taken to protect against deletion which can be accidental but can be otherwise.

russf2001
russf2001

I recently installed 4 Drobo Elite on a small 2 server Business Using veritas Backup to disk. I than copy backup files to second drobo for redundant failure. Monthly backups are 500gb usb drives put off site. Very fast iscsi very reliable. No need for body to change tapes.

radio1
radio1

We use Veeam replication that keeps multiple point that we can roll back to if necessary. We also backup using the Veeam product and can do file level restore that way. We also backup again at night to an off-site location. We also us a file level copying program for all crucial servers so the information can be accessed instantly if necessary. We also use other backup technologies. I am of the notion that if it can fail, it will. I use multiple ways of protecting my information and my job. My paranoia of data lose has saved my rear on multiple occasions. Best of all, its mostly automated. I am very interested in Veeam's new product to also test backups and verify them automatically. I don't work for Veeam, but I have been very satisfied up to this point.

it_junkie
it_junkie

Cost is a huge factor when looking at tape vs replication. One also needs to consider retention and in the end, even if you have a replication solution in place, data may make its way on to tape or another removable medium such as disk. Costs incurred when dealing with tape: - media - fire-proof safe(s) - man-hours for storage/retention/organization Costs incurred when dealing with replication: - software - bandwidth (both-ends) - physical storage (SAN/NAS) Generally tape is the most cost effective solution, replication is the easiest to implement/manage but the most costly especially if you factor retention into the equation. How scalable would your SAN be? I guess it all comes down to your data-footprint. There are solutions for everyone, the cloud is a good DRP solution, but not a long-term retention solution. I figure you will see more and more hybrid solutions in place as there isn't one solution that can address all of the data-protection needs but again it comes down to: - costs - data foot-print - RPO/RTO objectives (recover point + return to operation) - retention requirements

b4real
b4real

Maybe it was a duplicate!

jmarkovic32
jmarkovic32

For an enterprise, I would use a mix of snapshots and tape for compliance. If you're not already virtualized, I'd go virtual and replicate LUNs to a hot DR site. In the event of a disaster or failure, the main site would fail over to the disaster site.

bigjohn99999
bigjohn99999

we use use a product from GlobalScape called WAFS (Wide Area File Services) and we replicate critical files to a central site from 4 off site locations and from the central site its critical data another site. one of the best features is the ability to restore a deleted file without running a restore from tape and WAFS retains versions of files so it is easy to revert to a previous version. it self cleans with perimeters you set. we currently are replicating about 1.5 TB of data i then backup to tape also and each site backups their data also for redundancy.

Cerebral*Origami
Cerebral*Origami

Once full backups no longer fit on one tape I dropped from a nightly schedule to a weekly where I would come back into the company on Sat. morning to swap tapes. We finally ended up just using 1TB external USB drives. I can fit 3 full backups on each drive and swap them out each night. A very cheap and simple system. One of the drives stays with me at all times so, unless the company is hit by a meteor while I'm sitting in it, we have the offsite thing covered. :) The biggest drawback is that if a user erased something more than a week ago they're out of luck. And I don't have the historical 6 month backups I'd like to keep around.

gypkap
gypkap

This comment is based on reel to reel tape backup in the late 1980s, when I worked on evening backups. At least on large reel to reel tapes, there's sometimes a problem with print through. That is, there's a problem with one layer of tape affecting adjacent layers of tape, resulting in errors on the tape.

b4real
b4real

I'm a DroboPro user, and like the device also. I'd like to see how often you script it out or use DroboCopy?

joe
joe

backups are cheap compared to the value of lost data that would have to be re-entered or re-created as the origin is almost always labor intensive.

JLVFR
JLVFR

My tape-based TSM is chock full of data. I'm staring at: large expansion of a tape system, a new, greater capacity tape system or a replication/SAN system. Either way, I'm going to spend loads of cash...

Tink!
Tink!

seeing as how our tape drive is having no end of failures lately. I think I need to replace the whole drive. My employer however, would not be willing to pay for or trust an off-site solution since it would have to be a 3rd party because we only have 1 location.

b4real
b4real

But if the off-site requirements are selective, many organizations may simply be able to replicate and use existing bandwidth. There are storage costs on the other end. But most importantly, I think it more reliable.

b4real
b4real

BigJohn: Compelling solution. What bandwidth is required for that solution? Secondly, is there a local write cache that is queued on the backend?

lgarfield
lgarfield

I've used a Drobo device as a target to replace tapes. It uses USB2 or Firewire to connect to your server. Then you can populate it with inexpensive SATA drives. Of the four available slots, I use three 1TB drives. The Drobo sets them up as RAID so if one drive fails, your data set is still intact and is easily rebuilt by replacing the bad drive. And you can mix and match drive sizes, speeds, and manufacturers. When the drives are nearly full, I remove & label them and store them as a backup set in a fireproof media safe. Easy enough to take them offsite for DR. One caveat: the drives are ONLY readable in a Drobo device because of the proprietary RAID. And last I checked, the disks are only readable in the same model of Drobo, so you might have to buy two of the same device and store one offsite with your archive disks. It's not encryption by any means, but a limiting factor for data leakage. The big upside is the devices and the SATA disks are real cheap. The downsides are that the device is really intended for SOHO direct attached storage and the read/write speeds are mediocre. -- I don't work for or sell Drobo, just an impressed customer.

paradoxstorm
paradoxstorm

You could purchase a 5 or 8 bay hard drive enclosure and set it up as a JBOD instead of as a RAID, then hot swap the drives just like you would a tape drive. It's an eSATA setup, and you'd need to buy a card. We just switched to this at work lately and it's working quite nicely. I'm backing up about 100GB nightly in about 3-1/2 hours. Plus, as far as cost goes it's extremely cheap. As far as getting a 3rd party for offsite rotation, it is very worth it. I work for a records management company. Most places that offer tape/hard drive rotations store your data in fireproof media vaults that are continuously monitored for temperature and humidity as well as CCTV. Plus it's convenient to have the drive show up on a regular schedule to swap them out.

radio1
radio1

We off-site to the owners house. We are only 1 site as well. We do this nightly and find it very feasible.

it_junkie
it_junkie

There are other mediums out there such as removable disk. Sounds like a colo isn't an option due to cost, you could leverage a service such as Iron Mountain to come pickup the media monthly.

LutterworthT
LutterworthT

I have successfully used solid state drives as a better, cost effective alternastive.

lgarfield
lgarfield

If you are looking for a little more of a SMB backup/DR/replication solution, there is a solution from Revinetix that is appliance-based. It uses SATA drives and one slot acts as an "archive" slot for a large, removable drive for offsite DR. This solution includes unlimited agents for servers, desktops, and laptops (Win, Mac, Linux) and doesn't require any third party backup software. As a future option, you can purchase another appliance and set up replication between the two. It also does file-level deduplication. If you are looking to completely replace your backup solution, you might want to look at this. -- I also do not work for or sell Revinetix products, but just an interested potential customer.

b4real
b4real

Virtual Tape Library rolls like that.

jeslurkin
jeslurkin

I'm wondering if DVD-RAM might be more reliable,... and therefore useful,... at least for the small/home office.

yattwood
yattwood

In the bad old days, I used to take THREE (3) DAYS to do an 'scp' copy of a 1.6TB Oracle 8.1.7.4 database from the production to the development servers (for 10+ years, I have vainly tried to convince the developers that FULL-SIZE COPIES OF PRODUCTION aren't necessary - but I lost that battle) We then implemented Network Appliance SnapMirror and FlexCloning - after the initial setup (about 1.5 weeks) - I regularly refresh their development databases (all full-sized) in ONE HOUR AND THIRTY MINUTES - I destroy the previous FlexClones, create new ones, mount, and do a 'recover database using backup controlfile' - and voila - a lovely 1.6TB Oracle 8.1.7.4 database in the development environment. Current production is in Northern California; development is outside of Chicago, Il - we've throttled the network (although the network guys would love to throttle the DBA's - we are definitely on their hit list...) so that we aren't taking up TOO much of it (but hey, I'm a DBA - there is NO SUCH THING as TOO MUCH disk, memory or bandwidth.......)

david.hunt
david.hunt

DVDs written by the state-change dye process as distinct from the mass production pressing process aren't all that reliable. Although we think of them as digital media, the reality is that they are analogue and the signal to noise ratio is very dependent on the combination of drive make / model and DVD manufacturer (not to be confused with brand, as many brands source from more than one manufacturer). The result, assuming you don't get a coaster to start with, can be a DVD that is readable but has almost the limit of errors that can be recovered through the forward error correction intrinsic to the format. This means that as the DVD deteriorates, it suddenly reaches the point that the error rate reaches the unrecoverable level and you have unrecoverable data. Once you reach that point it is too late, and there's no warning. Unless you measure the actual error rates and reburn DVDs that are marginal this is a bit hit and miss. Measuring the actual error rate is time consuming and requires special software as well as drive firmware that allows it. The errors are corrected in the drive, so the computer doesn't know about it. Removable disks, USB attach disks and USB Keys with an appropriate rotation schedule are better and less costly for small businesses. One must still be alert to the possibility of device failure, but it doesn't usually occur with these devices while they are off-line (and not powered). Archival is a separate problem altogether.

radio1
radio1

Youngest kid is in 40s, but still can destroy Ultrium tapes. Defiantly has a fire safe. In fact he has a "fire proof" 4 drawer filing cabinet that weights more than anything should be allowed to. We also backup to DVD (bunches of them) monthly and save somewhere. He takes them and i really don't know where they go. Paranoia is a trait every IT person should have.

justmathew
justmathew

Does the owner have a fire safe and kids? Call me a pessamist but it is not beyond reasonable doubt to imagine that anyone maliciously targetting the company might also have a grudge against the owner so a fire safe for me would be essential, it also keeps tapes and kids apart, ever seen what 'fun' a child can have with an Ultrium tape...?

JLVFR
JLVFR

... I may not have a choice. I'm looking at either a completely new inhouse system or cloud. When you compare the costs...

b4real
b4real

Loosely speaking, of course. I did not include it to try to pin the top two solutions against each other: Tape and replication.

JLVFR
JLVFR

Thanks for the info anyway. :)

raoullux
raoullux

Difficult to say. We use an external co. They uploaded all our tapes so that historical backups remained available. The biggest backup is the seed backup as it is a full backup of all servers. That was probably several TB. Every following backup is smaller as they are incremental. But the software is managing that. The customer sees them like full backups. Then not to forget the leased line (fiber) to the provider.

JLVFR
JLVFR

Do you have any idea how much data you have on backups? I'm studying online backups too, and need to find solutions fast...

raoullux
raoullux

what about online backup ? We switched from tapes to online backup about 3 years ago when we had a collection of 6 daily tapes (monthly rotation so 186 tapes). We then switched to a system like evault. I don't know the cost but in terms of speed and ease of use it is perfect.

JLVFR
JLVFR

Do you keep them in your datacenter, are they outside, or do you send them out regulary?

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