Tape Backup Software. Server and LTO Tape Backup Solutions

Despite the inroads made in large scale disk backup and backup to cloud strategies, magnetic tape backup software remains a major component of many data protection architectures. Tape provides advantages that are hard to replace with any other technology. Factors such as data write speed, portability, reliability, ease of storage, and data density all contribute to the ongoing popularity of tapes. Bacula Enterprise supports tape libraries of all vendors, sizes, and types, in addition to cloud and disk backup, giving the customer total flexibility in storage media. This how-to will describe some of the basic setup steps and configuration notes for using tape backup software solution for most libraries from Bacula Enterprise.

But first there’s a topic worth exploring: the reasons for choosing tape over other storage types, such as disks. Next we’ll go over some major advantages and challenges of both disks and tapes.

Disks are a well known storage medium, requiring little to no maintenance and their scalability is quite good in general. One of their main advantages is recovery time – allowing for easier access to specific files from your backup. There’s also all the advantages of deduplication, which is essentially the deletion of all duplicated data at an extremely granular level, so your backups typically take much less storage space.

Tape storage and other storage types

However, there are some limitations when it comes to using disk as data storage. For example, a data that is kept on disks may be more susceptible to accidental overwrite or deletion, and can become a target of specific computer viruses. Disks can also be relatively costly when it comes to upkeep, since they’re always “working” and can become overheated, which means you’ll need both a means of cooling and providing power for the whole system to work properly. At the same time some people might think that relying on cloud backups would solve those problems – but cloud storages quite often use literally the same disk types as everyone else – merely providing you with access to them. This means most of these issues remain.

Of course, cloud storage as a backup target has its own benefits, and it is possible to segregate four major advantages that cloud backup alone can provide:

• Convenience, since cloud backups could be accessed from any location that has an internet connection, making it far easier for the IT department to monitor and manage all kinds of backup and restore operations.
• Safety is also a point of interest in terms of cloud backups since the existence of cloud backups allows for its users to avoid all kinds of travel restrictions, including lockdown orders, as well as many others.
• Ease of use: cloud backups are often easy to set up and use in comparison with other options, and it is even possible to automate most of the backup process, making it easier for the IT department to monitor everything.
• Snapshot capabilities are quite convenient in this case, too, since cloud backup as a whole makes it far easier to generate and store snapshots for various purposes.

Then there’s tape, which is relatively old as a storage in means, but is still certainly reliable enough to be considered as a proper storage alternative. One of the biggest advantages of tape is its capacity – LTO-8 standard allows for up to 30 TB data per single tape unit (and future standard LTO-12 promises to reach the overall capacity of up to 480 TB per tape).

LTO – Linear Tape Open is a tape storage technology format that is considered one of the most popular in the tape market. It has the largest potential storage capacity in comparison with other formats, as well as even bigger compressed capacity. LTO tape backup is perhaps the best open-format tape technology out there when it comes to storing a variety of different content.

The current LTO generation is LTO-9, released in September 2021 and offering up to 18 Terabytes of raw data capacity, with compressed capacity being even higher – up to 45 Terabytes. There are also three more generations to be expected in the near future – with the prospect of up to 144 Terabytes of raw and 360 Terabytes of compressed data in LTO-12.

Storage capacity is not the only parameter that changes and improves with each LTO generation, though – there is no shortage of additional features being added, such as WORM capabilities being added since LTO-3, encryption capabilities – since LTO-4, LTFS capabilities – since LTO-5, as well as number of partitions (from 1 at LTO-1 to 4 since LTO-6).

However, that’s not to say that LTO is the only real option. There are at least four other tape formats that have their own advantages and limitations. For example, there is AIT – Advanced Intelligent Tape, a format of data storage that has been developed by the technological giant Sony. This format is also general-purpose, just like LTO, but it offers slightly different storage parameters – AIT gen 5 has 24 MB per second data transfer rates and can keep up to 400 Gigabytes of data.

Speaking of general-purpose, there is also a tape format made specifically for backups of personal computers – QIC, or Quarter Inch Cartridge. It is a magnetic tape format with a possible capacity up to 25 Gigabytes. On the topic of tape storage technologies for specific purposes we can also mention DAT – Digital Audio Tape, which is a tape storage medium mostly aimed for audio storage purposes. DAT can have up to 80 Gigabytes of storage capacity on a tape that can be from 60 to 180 meters long.

The last, but not the least, participant of this list is another relatively popular tape storage format – DLT, or Digital Linear Tape. This is most likely the second popular tape format on the market after LTO tape backup, offering data written in either 208 or 128 linear tracks. Its storage capacity is up to 70 Gigabytes per unit, with their newer SuperDLT version supporting up to 300 Gigabytes of storage capacity.

Price of a tape backup is a key point, as well. Tape is considered one of the cheapest storage choices there is when it comes to long-term data storage. It is used in some cloud services, too, and the offsite vaulting of tape in general allows the data to escape ramifications of a natural disaster or some other type of occurrence that might harm your data on-site.

Complexity is also something that may be relevant to tape backups – the entire process can sometimes require constant surveillance, thorough planning of the entire process, as well as using something called a backup rotation scheme.

In some cases, you may need a new tape cartridge for each and every backup cycle. It is also possible to reuse tape cartridges from previous backups, as well, making it a much more cost-effective approach as a whole. Generally speaking, it is possible to segregate three main backup rotation schemes in tape backups:

• GFS scheme. The most reliable option out of the three, the Grandfather-Father-Son scheme is also the most popular backup rotation scheme out there. It relies on keeping multiple levels of backups, from daily to weekly and monthly backups. One potential issue with this approach is that it is probably the least cost-effective, requiring more tape to execute properly – and thus, generating a higher upkeep cost for the company in question.
• Tower of Hanoi. A backup rotation scheme that acts as a sort of a middle ground between the most expensive and the most affordable ones, Tower of Hanoi is at its best when working with small or medium-sized businesses with relatively small data volumes. While it does cost less than the GFS scheme, it is also rather complicated in its implementation, creating a high possibility for an error to be made when swapping tape cartridges. Additionally, this rotation scheme has a requirement of a full backup for each of its sessions, making the entire process rather long and storage-intensive.
• Five-tape scheme. The most cost-effective option out of the three, the five-tape rotation scheme is at its best when used for smaller businesses that do not have the requirement of archiving outdated information. It works on a relatively simple principle of reusing tape cartridges every single week, keeping one tape cartridge for every working day of the week. It is worth noting that, for this rotation scheme to work, the company’s daily data volume should not exceed a single tape cartridge’s capacity.

Proper upkeep conditions will allow tape to stay sound for a long time with no damage to the data in question. The general tape lifespan is considered to be around 30 years. There’s also the nature of tape backups – they aren’t “plugged in”, as soon as the backup is done – the device itself goes offline, and that saves the data within from potential cyberattacks and such.

Unfortunately, tape isn’t perfect, either – it requires specific conditions to prevent data deterioration, general recovery times are much longer than most of the alternatives due to the need to physically get the tape in question to your working environment, and navigation within that data has more limitations than disk. Even with the most recent developments, such as linear tape file systems (LTFS) – it’s still nowhere close to that of disk searching speed.

Tape is also prone to a number of issues, including incorrect tape media, invalid backups, and so on. For example, using an unprepared or unrecognized tape media is a surprisingly common mistake in this field – even though the tape backup software should be able to notify its user if it manages to locate one or more cartridges like this. All of this is possible thanks to a unique barcode that each tape cartridge has.

Invalid backups are also an important factor when it comes to common tape backup mistakes. The risk of creating an incorrect or invalid backup without knowing it is always there, which is why it is so important to perform regular error checks, as well as a regular backup verification process, regular test restores, and a regular full backup (at least once a month) – all of that is done to minimize the potential damage of losing some, if not all, of your primary data.

Speaking of testing – tape backup testing as a whole is unpopular, with roughly 34% of businesses failing to test their tape backups in the first place, and about 77% of the ones that tested their backups found some sort of tape-related backup issues (source).

Despite its limitations, tape is still considered to be one of the most convenient storage types when it comes to long-term data storage – and in that regard, tape prevails over most of the alternatives.

Tape backup: misconceptions and benefits

The Bacula Enterprise Storage Daemon is the component that manages reads and writes to the various storage devices supported by Bacula. Tape backup is managed in part by native Linux tools and therefore supported devices largely follow support in the Linux kernel. For information about whether or not a specific tape library or drive is supported by Bacula Enterprise, Bacula Systems support can answer the question. However, most commercially available tape libraries and drives that are supported by the Linux kernel are supported by Bacula.

There are some common misconceptions about tape. We’ll walk some of the most popular ones:

Tape backup is dead. The only thing that’s dead about tape as a backup medium is the marketing efforts! A lot of companies still use tape in their backup systems. The lack of general understanding of the technology behind tape as a storage type prevents people from realizing the possible benefits of using tape as a backup storage medium. Partial blame for that can be laid upon tape vendors, they do little to educate against negative rumors and misconceptions.

Tape as a storage medium can be replaced. There are specific tape benefits that often, no other storage type can match as easily. High capacity is one of those, keeping large amounts of data on tape is considerably cheaper than using any other medium. For compliance purposes a lot of companies prefer tape over cloud to store their data intact and offsite at the same time. And tape’s offline capabilities allow it to naturally evade most of the cyberthreats of the modern age. They also require less power and generate less heat than other storage types like disks.

Tape is ineffective as a storage. It’s true that tape has its limitations, but it’s perfect for offsite data storage purposes and plays its part in long term data retention really well. There’s a well known strategy about backups, it’s called 3-2-1 rule: this where you should keep three different copies of your data stored within at least two different types of storage and at least one copy must be kept off site – and tape backups are a perfect medium for playing part in that strategy, since its storage capabilities are huge, and when used as an offline storage, make it almost impenetrable by modern cyber threats.

Tape as a data storage technology is old and outdated. It’s worth remembering that tape is basically the only storage medium that has been stable since it was created, with much less rises or declines in popularity, like disk or cloud storage experiences.

There is no future for tape backups. Due to tape’s reputation as a “dead” storage type, a lot of people think that it’s not evolving and has no future in general. This is not true; over 80% of modern companies of different sizes use tape backup as one of their means of storing data. More than that, recent years show the increase in this technology in general, and tape manufacturers are doing their best to improve tape as a storage medium in general, including not only capacity, but also data encryption within tape, data partition to lessen the overall backup complexity, and other optimization technologies.

Some people may be questioning the reasons to use tape in general, when it seems many are moving away from physical storage to the cloud. There are several reasons for that:

• Durability – as mentioned before, with proper care tape is able to store data for about 30 years, which is a significant amount of time in general, and all of that without any regular maintenance. This puts most of the HDDs, SSDs and other storage mediums in shame in comparison.
• Security – modern tape formats like LTO-Ultrium offer data encryption over tape to ensure compliance with all kinds of laws and standards when it comes to data security. Knowing where your tape backup is physically stored is also considered to be a major advantage when it comes to the requirement of physical control over a company’s data.
• Portability – despite its capacity in general, tape is generally quite easy to store, especially when compared to cloud systems or hard drives of any kind.
• Conversion prices – some older companies don’t have the required funds to perform the migration to some other data storage medium or to include another one alongside tape. Full data storage conversions generally require an incredible amount of both work and funding, add to that all of the work about changes in policy – and it’ll be a good enough reason for companies to continue using tape despite everything.
• Compliance – some organizations find it easier to use tape as a way to meet compliance laws and obligations, for example some banks and legal institutions.

Tape backup software providers

Tape backup is supported by a large number of third-party backup software providers, even if it is not obvious from the first glance. In the list below, you can see 8 different examples of backup software providers that can work with tape backup and restore operations:

A rather popular backup solution that also supports backup to tape – including operations such as tape discovery, tape loading/unloading, tape deletion, and so on. Additionally, two of Commvault’s own features can be applied to tape backup. There’s the Export Media – the ability to physically remove media from the tape storage, and there’s also the Vault Tracker – the ability to manage media that is stored on offsite locations (which is the primary use case for tape backups in general).

Arcserve is a data protection solution that offers multiple different plans to its clients, with each plan being more suitable for a specific target audience. Its tape backup solution capabilities are more suitable for data centers, offering multiple different features to counteract some of the common tape problems. As such, Arcserve provides centralized reporting (SRM), granular recovery for multiple different instances, smart restore capabilities, and also meets the requirements for various backup-specific tactics, such as D2D2T, D2D2C, VTL, etc.

Another example of a well-known backup platform on the market that also works as a tape backup software. Veeam’s capabilities in terms of tape backup include the ability to create a backup of everything from the Windows servers, the Linux servers, as well as the NDMP and the NAS devices. It supports both full and incremental backup types and has specific “backup to tape” jobs that offer more options for tape as the backup target storage specifically.

BackupAssist lives up to its name, offering a comprehensive backup solution for Windows Server, Microsoft 365, as well as work-from-home environments. Its BackupAssist Classic package offers an abundance of features for data protection, and it is also the only option that supports tape backup. BackupAssist has a rather impressive list of features when it comes to server tape backups, such as data encryption (AES-256), tape labeling, full/incremental/differential backup support, data compression, quick and easy installation/management, multiple notification methods, and more.

Moving on towards smaller backup solutions, NovaStor offers a comprehensive backup solution with an impressive feature set. It supports Windows, Linux, and VM workloads, capable of operating with SharePoint, Active Directory, MS Exchange, as well as other apps. There are also multiple different features worthy of a great server tape backup solution, such as virtual tape libraries, cloud storage support with multiple storage providers, deduplication, dynamic tape drive sharing, and so on.

Many tape-specific features could also be found in Iperius Backup – a backup solution for databases, virtual machines, and other workloads. As for the tape-related features that Iperius Backup can offer – there’s drive imaging, data encryption, support for VSS (Volume Shadow Copy), support for all of the different tape drive variations (LTO tape backup, as well as DLT, AIT, DAT, and more), and granular restoration. It can also backup on multiple tape locations at once, automate some of its features and can automatically verify and/or eject tape cartridges.

EaseUS is an entire family of products that offers multiple different software appliances for partition management, data recovery, data transfer, and, of course, backups. EaseUS Todo Backup is a versatile backup solution that has a number of useful backup-related features, including supporting tape as a backup location, as well as incremental backups, one-click backup/recovery operations, extensive scheduling, and many other features for both regular users and businesses.

The last, but not the least example on this list is Bacula Enterprise – a multifunctional backup solution that supports an abundance of different storage types and backup techniques with the help of its modular system.

Bacula Enterprise offers a highly secure modular architecture that places it in the highest bracket of solutions regarding its security levels. Being especially compatible with tape storage technology is part of that security architecture, for users that have tape storage as part of their security strategy. Bacula also has some advanced tape-related features:

• Labeled Volumes, preventing accidental overwriting (at least by Bacula). Bacula Enterprise also supports IBM /ANSI tape labels, which are recognized by many enterprise tape-managing softwares
• Data spooling to disk during backup with subsequent write to tape from the spooled disk files. This prevents tape “shoe shine” during Incremental/Differential backups
• Support for autochanger barcodes; automatic tape labeling from barcodes
• Automatic support for multiple autochanger magazines either using barcodes or by reading the tapes

Here are some examples of tape libraries and autoloaders that are known to work with Bacula Enterprise tape backup software:

• DELL PowerVault TL4000
• Qualstar RLS-8450
• StorageTek L180
• Oracle StorageTek SL500
• Oracle StorageTek SL3000

The exact specifics of how Bacula Enterprise Storage Daemon handles tape backup would be discussed below.

Tape backup with Bacula Enterprise

While most tape backup and recovery drives will work with very little configuration, there are some main things to be aware of in order to have the best possible performance and reliability. Bacula Enterprise has a web interface, BWeb, which greatly simplifies setup and provides sensible defaults, it’s good to have an understanding of what is going on underneath in the configuration files. To get an idea of how BWeb manages creation and configuration of autochangers, please watch the video:

This video is related to installing a deduplicating disk autochanger, but the same wizard and process are used to install tape devices. The information that follows should help fill in any gaps when setting up a tape autochanger, or allow you to set up tape autochangers without the help of BWeb.

By default, Bacula Enterprise is installed with a number of functional example configurations. We are going to take one of those examples and customize it a bit to make it look closer to what we could actually use – the example we’re going to use is the tape autochanger one (because Bacula Enterprise uses the word “autochanger” to describe the tape library as a whole).

# An autochanger device with two drives
#
#Autochanger {
# Name = Autochanger
# Device = Drive-1
# Device = Drive-2
# Changer Command = “/opt/bacula/scripts/mtx-changer %c %o %S %a %d”
# Changer Device = /dev/sg0
#}

# An autochanger device with two drives#Autochanger {# Name = Autochanger# Device = Drive-1# Device = Drive-2# Changer Command = “/opt/bacula/scripts/mtx-changer %c %o %S %a %d”# Changer Device = /dev/sg0#}

#Device {
# Name = Drive-1 #
# Drive Index = 0
# Media Type = DLT-8000
# Archive Device = /dev/nst0
# AutomaticMount = yes; # when device opened, read it
# AlwaysOpen = yes;
# RemovableMedia = yes;
# RandomAccess = no;
# AutoChanger = yes
# #
# # New alert command in Bacula Enterprise 8.8.0
# # Note: you must have the sg3_utils (rpms) or the
# # sg3-utils (deb) installed on your system.
# # and you must set the correct control device that
# # corresponds to the Archive Device
# Control Device = /dev/sg?? # must be SCSI ctl for /dev/nst0
# Alert Command = “/opt/bacula/scripts/tapealert %l”
#
# #
# # Enable the Alert command only if you have the mtx package loaded
# # Note, apparently on some systems, tapeinfo resets the SCSI controller
# # thus if you turn this on, make sure it does not reset your SCSI
# # controller. I have never had any problems, and smartctl does
# # not seem to cause such problems.
# #
# Alert Command = “sh -c ‘tapeinfo -f %c |grep TapeAlert|cat’”
# If you have smartctl, enable this, it has more info than tapeinfo
# Alert Command = “sh -c ‘smartctl -H -l error %c’”
#}

#Device {
# Name = Drive-2 #
# Drive Index = 1
# Media Type = DLT-8000
# Archive Device = /dev/nst1
# AutomaticMount = yes; # when device opened, read it
# AlwaysOpen = yes;
# RemovableMedia = yes;
# RandomAccess = no;
# AutoChanger = yes
# # Enable the Alert command only if you have the mtx package loaded
# Alert Command = “sh -c ‘tapeinfo -f %c |grep TapeAlert|cat’”
# If you have smartctl, enable this, it has more info than tapeinfo
# Alert Command = “sh -c ‘smartctl -H -l error %c’”
#}

Let’s break this down a bit. To make a better configuration, we’d need to make just a few changes. First, it should have a better name to avoid confusion in the future. Our first few changes are going to be mostly about changing the autochanger name at the beginning of a command – to avoid confusion in the future. The device names here can change to match as well, as they are just references to the device resources we’ll look at next. Next, it’s best to use the udev device name rather than the ‘/dev/sgX’ device path, as the udev name will never change on a reboot. So that will look like ‘/dev/tape/by-id/scsi-xxxxxxxxxxxx’ The changer command usually doesn’t need to change, and you can view the script in ‘/opt/bacula/scripts/’ if you want to see how it works. So the example below is closer to a production config:

# An autochanger device with two drives
#
#Autochanger {
# Name = HPLTOLib1
# Device = HPLTOLib1-Drive-1
# Device = HPLTOLib1-Drive-2
# Changer Command = “/opt/bacula/scripts/mtx-changer %c %o %S %a %d”
# Changer Device = /dev/tape/by-id/scsi-xxxxxxxxxxxx
#}

Next, let’s look at the tape devices. As with the autochanger itself, we’ll want to rename the devices so it’s clear which device ‘owns’ them. In this case, the names must match the names in the autochanger config. We’ll also want to use the udev persistent names, as you can see below. The drive index is important; when mtx-changer issues a command such as ‘load tape x into drive y’, it uses the drive index from this device setting to determine where the tape will go. So this must match what the library itself understands the drive numbering to be. Usually it starts with drive 0.

The Media Type is an arbitrary designation given to devices within a tape library to tell Bacula which devices can be called to operate which tapes. Tapes are labeled with a media type as well. This means that, for example, if you have two LTO-7 tape drives in library A, and two in Library B, it may be best to give them different media types so that Bacula doesn’t request a mount from Library A to Library B. So in this case, we’ll the the media type to the autochanger.

Always Open means that Bacula will not rewind the tape after each write session, but rather leave the drive ready for the next append. Automatic Mount means what it sounds like; Bacula will mount and use the tape devices without user intervention. Removable Media tells Bacula that the media may not always be available in the autochanger and changes the behavior when a new tape is needed. Random Access is set to ‘no’ as tapes are read and written in a linear manner, and finally Bacula needs to know that the device is a member of an autochanger. Bacula Enterprise can also use the sg3-utils packages to send tape alert and monitoring commands, and alert you if a drive is showing errors. So the config below is pretty good, and can be copied for the second drive with just a change to the name, drive index, and archive device.

#Device {
# Name = HPLTOLib1-Drive-1 #
# Drive Index = 0
# Media Type = HPLTOLib1-LTO-7
# Archive Device = /dev/tape/by-id/scsi-xxxxxxx-nst
# AutomaticMount = yes; # when device opened, read it
# AlwaysOpen = yes;
# RemovableMedia = yes;
# RandomAccess = no;
# AutoChanger = yes
# Maximum Block Size = xxxxxxxx
# Maximum File Size = xxx
# #
# # New alert command in Bacula Enterprise 8.8.0
# # Note: you must have the sg3_utils (rpms) or the
# # sg3-utils (deb) installed on your system.
# # and you must set the correct control device that
# # corresponds to the Archive Device
# Control Device = /dev/sg?? # must be SCSI ctl for /dev/nst0
# Alert Command = “/opt/bacula/scripts/tapealert %l”
#

So with the above, we could very likely have a working configuration that can load, unload, read, and write volumes. What are the next steps? First, there is a command line tool called ‘btape’ that should be run before putting anything into production. Please note that btape will destroy any data on a volume, so please use a blank tape! Within btape, there are commands to test the autochanger, test writing a full tape and making sure it can be read back, as well as performance testing tools. A successful run of the ‘btape test’ for each device, and ‘btape autochanger’ should be considered a minimum requirement.

Finally, for performance, the ‘maximum block size’ and ‘maximum file size’ should be set for each device. The values here that will yield the best performance depend mostly on the tape drive technology. Sensible defaults are set by BWeb, or can be provided by Bacula Systems Support. Block sizes usually range between 64-512k, and file size anywhere from 1-5GB. It’s best to get the current recommendations from Bacula Systems Support when possible, and then apply them and test using the btape speed test. Please note that block sizes can’t be changed easily once in production, so take the time to test beforehand.

Conclusion

Hopefully this has been a helpful overview of how to set up tape backup software in Bacula. As always, the Bacula Main Manual has detailed information about each configuration option, as well as more example configurations. For Bacula Enterprise customers, please don’t hesitate to contact support with questions as you set up tape devices.