Backup media choices for FreeBSD servers

[Olivier Nicole]

> I need to implement an automated backup facility on the FreeBSD file
> server I'm setting up for a client. It will have a software RAID 1
> Mirror/Duplex that is made available to Windows XP SP2 and Windows
> Vista Home Premium users as a Samba share.  I also plan to create
> system recovery disks (disk images) for the server and each Windows
> client.
> 
> This leaves backing up user data on some schedule. I've read "Backup
> Basics", but have some questions:
> 
> Which is best backup media for a FreeBSD file server, based on known
> issues (or lack of) with each format? I need to decide between the
> following formats:

>  a) CD-R (or CD-RW?)
>  b) DVD-R (or CD-RW?)
>  c) Streaming tape (which format/standard?)

For years I have been using Amanda (in the ports) to backup any
servers, including Samba server, as well as some disks from PC under
Windows, saving the data on a SLR 100 (Tandberg) tape.

Tape dirve is expensive (and maybe out of production), tapes are not
cheap, but they are reliable. Now days I would choose LTO technology I
beleive. At any cost I would avoid any kind of DAT format: it acheives
the capacity by high compression of the data on the tape and so the
reliability is really an issue, plus the rotating head wears the tape
much uch faster than any linear reccording technology.

> Which is the best method for backing up data files on a Samba sharer
> FreeBSD?  Handbook says dump is the only way to go.

I never looked at that part. I am using tar because it is a very
universal format: the next server could be a Linux box, the tapes
would still be readable, compared to dump that tend to be specific for
each operating system.

> Is it possible to have a Windows client perform the backup files on
> the Samba share to a local Re-Writable CD or DVD drive? If the
> answer is YES, what are the pros and cons of a UNIX-based (data-file
> only) backup vs. a Windows-based one?  Please add to my list of pros
> and cons:

Of course it is possible: any file that the Windows machine can access
through the network, it could back-it up.

> Windows Backup:
> PRO: Backup can be restored to a Windows drive while server is being fixed?
> CON: Users might forget to replace backup disk after using optical drive.
> 
> FreeBSD Backup:
> PRO: Out of sight from users (server is in a storeroom).
> CON: Cannot restore backup to a Windows disk while server is being fixed?

Except if your tape drive is dead, fixing the server is really a
matter of a couple of hours: at least fixing the server enough so you
can restore something from a backup tape. I once was even able to
restore something from booting the server from the recovery boot...

I would consider it a highly bad luck that the server is dead and at
the very same time you need to do a restore.

> These are some of my other considerations:
>  
>  1) Cost is a primary concern. Budget does not allow for a
>  1) multi-drive solution. Best if client does not handle backups
>  1) (change discs/tapes), so a solution that permits storing several
>  1) backups to same disc/tape preferred.

Tape is expensive. My future choice, when I have to replace the
existing backup server is virtual tapes on some big hard disk (500GB
SATA type of disk). Only thing to be found is the way to swap the hard
drives.

> 2) I only want to back up user data (not the OS). Current user data
> 2) occupies less than 1GB of drive space, and is expected to grow at
> 2) a modest rate.

Then install one disk and use some kind of virtual tapes on it. But
that would not allow off site storage unless your disk can be moved.

According the size of the data, you may consider USB connection.

> 3) I do NOT have a writable CD or DVD drive (but can buy one if not
> 3) too spendy).
> 
> 4) I have an external SCSI connection, but very little "shelf"
> 4) space.
> 
> 5) The server does not have room for another internal device (except
> 5) if swapping out the existing ATAPI CD-ROM drive).
> 
> 6) I have an Ecrix Corporation Model VXI-1A SCSI internal tape drive
> 6) that I assume is obsolete (comments appreciated). Anyway, I don't
> 6) have room for it.
>  
> 7) Have not yet settled on a backup schedule. May be weekly or
> 7) monthly or ad-hoc, but daily is probably out of the question. The
> 7) RAID 1 array is expected to provide some degree of protection in
> 7) leieu of daily backups. Plan to back up all documents each time,
> 7) rather than implement a two-tiered backup process.

RAID 1 will not protect you against accidentally erasing a file. And
even though you informed your customer that the back-up is there just
in case of major system crash and does not cover the user mistakes,
they will come back to you asking to restore a file that they deleted
(Samba does not offer recycle-bin). So you can still think about daily
incremental back-up.

Olivier