At 8:58 AM +0100 9/18/00, Graham, Total Coverage Limited wrote:
>I've been using Retrospect very successfully for some while now, backing up
>our small Mac LAN to recordable CDs.
>However our company has grown some over time and the use of CD-R is no longer
>a real option as it takes too long to do a full backup of the 30GB or so of
>data on the LAN.
>I am therefore looking for an economical, reliable tape based solution that
>can handle the job.
>There seem to be many different ysstems available on the market, but rather
>than wade through a pile of manufacturer misinformation I thought I would come
>straight to the horse's mouth, so to speak.
>What works?
>Any help or pointers that fellow list-users might be able to offer will be
>gratefully received.

This is from a previous post on the list, from the beginning of 
August. I hope this helps, and I hope Larry (and the list) doesn't 
mind my reposting...

At 1:36 AM -0700 8/3/00, Larry Acosta Wong wrote:

>I've added the two OnStream drives (ADR50 and SC30) in the internal 
>SCSI configurations (wide connector if available). I've listed the 
>pricing I can get to keep the comparison prices consistent.
>Steve Rothman, the Eliant 820 is an Exabyte drive utilizing an 8mm 
>helical scan tape. The VXA-1 media $/GB price is also actually a bit 
>higher than you calculated
>                                               Media
>                                               $/GB
>Exabyte M2: 60GB,  12MB/s, $3777 ($80 media)  1.33
>Sony AIT-2: 50GB,   6MB/s, $3289 ($94 media)  1.88
>DLT 8000  : 40GB,   6MB/s, $3915 ($64 media)  1.60
>Sony AIT-1: 35GB,   3MB/s, $1913 ($88 media)  2.51
>VXA-1     : 33GB,   3MB/s,  $939 ($67 media)  2.03
>ADR50     : 25GB,   2MB/s,  $697 ($46 media)  1.84
>DDS-4     : 20GB,   3MB/s, $1072 ($33 media)  1.65
>Mammoth   : 20GB,   3MB/s, $2126 ($56 media)  2.80
>DLT 4000  : 20GB, 1.5MB/s, $1352 ($64 media)  3.20
>SC30      : 15GB,   2MB/S,  $438 ($41 media)  2.73
>Mammoth-LT: 14GB,   2MB/s, $1193 ($35 media)  2.50
>DDS-3     : 12GB,   1MB/s,  $777 ($16 media)  1.33
>Eliant 820:  7GB,   1MB/s, $1160 ( $8 media)  1.14
>DDS-2     :  4GB, .51MB/s,  $606 ( $7 media)  1.75
>-Native capacity listed, compressed capacity is typically 50% more
>-Sustained transfer rate listed
>-Cost is based on internal model with wide SCSI connector (if available)
>-VXA-1 tape drive is even cheaper through Ecrix July promo ($539)
>-Media listed is highest capacity format in single packs
>Here's how I personally chose which tape drive to go with:
>The way I figure, in order, the most important factors regarding the 
>tape backup system are:
>1. Reliability
>2. Performance
>3. Ease
>4. Cost
>Some of these items will be in different order for other people but 
>I think that reliability is always the most important factor in a 
>backup. (To stress my point, substitute the word "parachute" for 
>"backup." I'm sure you'll always choose the most reliable parachute 
>over any other.)
>Reliability: The key feature with a backup is the ability to restore 
>data and no tape system is 100% problem-free. But, only Ecrix makes 
>these ridiculous durability claims and actually backs it up with 
>extreme torture tests (boiling & freezing tapes). This is what 
>really got my attention on the VXA drives.
>Performance: You need to backup your users in the shortest amount of 
>time possible. If it takes you more than one night to create a full 
>backup, some users will go more than a day between backups thus 
>reducing your backup system's effectiveness. Plus, the less you 
>inconvenience your users, the less likely they'll keep "snoozing" 
>Retrospect when it starts a backup. But with a fast tape drive 
>you'll need a fast network and fast clients. Watch for the 
>Ease: higher capacity tapes reduce the amount of tape swapping that 
>needs to happen during a backup or restore. If it takes 5 tapes to 
>perform a full backup, then it'll take 5 nights before the full 
>backup is done and the first incremental backup can take place 
>meaning that some people will go 5 days between their full and 
>incremental backups. Ideally, a full backup will fit on a single 
>tape or you'll have an autoloader.
>Cost: lower = good but when computing the cost per GB, you must 
>factor in the cost of the tape drive as well. $7 media sounds really 
>appealing but weigh in drive cost, performance and storage capacity. 
>Below, I've computed actual cost per GB for my test scenario of 
>100GB total to backup, 3 storage sets.
>                   Tran                #Tapes  Total   True
>Model      (GB)   Rate    Price Media  Req'd  Price   $/GB
>VXA-1       33    3MB/s    $539  $67    12   $1,343   $3.39
>DDS-3       12    1MB/s    $777  $16    27   $1,209   $3.73
>DDS-2        4  .51MB/s    $606   $7    75   $1,131   $3.77
>SC30        15    2MB/s    $438  $41    21   $1,299   $4.12
>ADR50       25    2MB/s    $697  $46    12   $1,249   $4.16
>VXA-1       33    3MB/s    $939  $67    12   $1,743   $4.40
>Eliant 820   7    1MB/s  $1,160   $8    45   $1,520   $4.83
>DDS-4       20    3MB/s  $1,072  $33    15   $1,567   $5.22
>Mammoth-LT  14    2MB/s  $1,193  $35    24   $2,033   $6.05
>DLT 4000    20  1.5MB/s  $1,352  $64    15   $2,312   $7.71
>Sony AIT-1  35    3MB/s  $1,913  $88     9   $2,705   $8.59
>Mammoth     20    3MB/s  $2,126  $56    15   $2,966   $9.89
>Exabyte M2  60   12MB/s  $3,777  $80     6   $4,257  $11.83
>DLT 8000    40    6MB/s  $3,915  $64     9   $4,491  $12.48
>Sony AIT-2  50    6MB/s  $3,289  $94     6   $3,853  $12.84
>For this comparison, I've included the VXA-1 at the promotional 
>price since it's been extended through Aug and is available to 
>everyone. The total cost of DDS-3 is actually $134 cheaper than the 
>VXA-1 but the cost/GB is higher, it requires 27 tapes total (9 tapes 
>per storage set) and its transfer rate is considerably slower.
>So, it's probably fairly obvious that I went with the VXA-1 drive. 
>The promo price was so good that I bought two. This gives me a 
>pseudo-autoloader and also gives me redundancy in case one drive 
>fails. Am I concerned about the new-ness of the drive? Of course. 
>I'd prefer that there were multiple manufacturers and multiple media 
>sources. But, with the way hard drive capacity/usage is increasing, 
>I'll likely be in the market for a new drive after a couple of years.

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