At 8:58 AM +0100 9/18/00, Graham, Total Coverage Limited wrote:
>Hi
>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
>bottleneck.
>
>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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