Hi everyone,

It's time for me to look at a new backup strategy and I'm considering a DLT
array managed with Amanda (from "http://www.amanda.org"), but some people
have suggested I shouldn't even bother with DLT and go straight to LTO
instead.

LTO arrays are a significant order or magnitude more expensive on average
than DLT arrays with 1 or more DLT-7000 drives in them, which is the main
reason I've been initially angling towards a good quality DLT array.

Anyway, what are the advantages and disadvantages of each type of backup
media? My backup requirements are not ultra-massive super-secret
government-type backup 'farms' in size, just a small array with enough
capability to reliabably provide data backup (and recovery) services for my
small network of around 10 or so active systems.

Regards,

Craig.

-- 
 SUN RIPENED KERNELS - Surplus Sun Microsystems Equipment, Parts + Accessories
    Waterfall, NSW, Australia - Operated by Craig Dewick - Founded in 1996
Main site: www.sunrk.com.au - Ebay Shop: www.ebayshops.com.au/sunripenedkernels
  Ph: +612-9520-2547 - Fax: +612-9520-2557 - Mobile: 04-2163-0547 (int. +614)

In article <d3d54p$ap1$1@yoda.apana.org.au>,
 Kralizec Craig <cd@lios.apana.org.au> wrote:

> Hi everyone,
> 
> It's time for me to look at a new backup strategy and I'm considering a DLT
> array managed with Amanda (from "http://www.amanda.org"), but some people
> have suggested I shouldn't even bother with DLT and go straight to LTO
> instead.
> 
> LTO arrays are a significant order or magnitude more expensive on average
> than DLT arrays with 1 or more DLT-7000 drives in them, which is the main
> reason I've been initially angling towards a good quality DLT array.
> 
> Anyway, what are the advantages and disadvantages of each type of backup
> media? My backup requirements are not ultra-massive super-secret
> government-type backup 'farms' in size, just a small array with enough
> capability to reliabably provide data backup (and recovery) services for my
> small network of around 10 or so active systems.
> 
> Regards,
> 
> Craig.

How much data each night are you backing up?

What is you "backup window" during which time backups are done and 
applications must be down or setup to do backups (e.g. Oracle)?

How long do you need to keep it?

How many drives will you have?

Will the drives be on any sort of hardware maintenance contract (they 
should be as replacing tape drives should be a #1 priority so you have 
good backups daily)?

If you're going to do a centralized solution, how will you restore files 
to a totally down system that's lost a system disk if the tape drive is 
attached to another machine?

-- 
DeeDee, don't press that button!  DeeDee!  NO!  Dee...

On Mon, 11 Apr 2005 01:02:20 -0700, Michael Vilain wrote:

> In article <d3d54p$ap1$1@yoda.apana.org.au>,
>  Kralizec Craig <cd@lios.apana.org.au> wrote:
> 
>> Hi everyone,
>> 
>> It's time for me to look at a new backup strategy and I'm considering a DLT
>> array managed with Amanda (from "http://www.amanda.org"), but some people
>> have suggested I shouldn't even bother with DLT and go straight to LTO
>> instead.
>> 
>> LTO arrays are a significant order or magnitude more expensive on average
>> than DLT arrays with 1 or more DLT-7000 drives in them, which is the main
>> reason I've been initially angling towards a good quality DLT array.
>> 
>> Anyway, what are the advantages and disadvantages of each type of backup
>> media? My backup requirements are not ultra-massive super-secret
>> government-type backup 'farms' in size, just a small array with enough
>> capability to reliabably provide data backup (and recovery) services for my
>> small network of around 10 or so active systems.
>> 
>> Regards,
>> 
>> Craig.
> 
> How much data each night are you backing up?

This is probably the key factor in my opinion.

> What is you "backup window" during which time backups are done and 
> applications must be down or setup to do backups (e.g. Oracle)?

Hopefully any key critical systems have a OS that supports snapshots,
and the backup window is effectively 24 hours :)

As regard to the original post, good look getting new DLT7000 drives.
They have not been in manufacture for several years now. Even DLT8000
drives stop production last year. You might also want to consider SDLT,
which gives better capacities and speeds per tape on a par with LTO.

On a side note does anyone have any experience of the SuperAIT drives
and tapes? Basically AIT in a 1/4" DTL/LTO sized cartridge. The specs look
good on paper; 500MB native capacity per tape, with 30MB/s native transfer
speed. However it is helical scan something I am not a great fan of.

JAB.

-- 
Jonathan A. Buzzard                 Email: jonathan (at) buzzard.me.uk
Northumberland, United Kingdom.       Tel: +44 1661-832195

In comp.unix.solaris Kralizec Craig <cd@lios.apana.org.au> wrote:
> Hi everyone,
> 
> It's time for me to look at a new backup strategy and I'm considering a DLT
> array managed with Amanda (from "http://www.amanda.org"), but some people
> have suggested I shouldn't even bother with DLT and go straight to LTO
> instead.
> 
> LTO arrays are a significant order or magnitude more expensive on average
> than DLT arrays with 1 or more DLT-7000 drives in them, which is the main
> reason I've been initially angling towards a good quality DLT array.
> 
> Anyway, what are the advantages and disadvantages of each type of backup
> media? My backup requirements are not ultra-massive super-secret
> government-type backup 'farms' in size, just a small array with enough
> capability to reliabably provide data backup (and recovery) services for my
> small network of around 10 or so active systems.

First of all, consider this: The DLT8000 manufacturing was stopped about
a year ago. The DLT7000 sometime before that. These are seriously obsolete
drives.

We've migrated from DLT700 and DLT8000 to LTO2. We found that the DLT7000
was flakey, with at least one drive failing every month (out of 16 total).
The DLT-8000 was decidedly better, but still failed more than expected.
Curiously, we didn't have a lot of read errors with either media, but we
also treated it fairly delicately.

LTO2 is an order of magnitude more reliable. Going from 16 DLT8000 drives
down to 6 LTO2 means that our duty cycle is about the same (also factoring
in a lot of schedule changes and better coverage). Haven't had a failure
yet of ANY sort (media, soft drive, or hard drive), in five months. Our
other library went from 16 DLT7000 to 10 LTO2, and over two months have had
the same results.

Conversely, I know of quite a few people who have had quite a lot of
problems with the original LTO. I've never worked with it, but anecdotally
I'd stay away. At the very least, I'd consider a SDLT 320, and if you can
justify the price, an LTO2.

Colin

On Mon, 11 Apr 2005 23:00:41 +0000, Colin B. wrote:

> In comp.unix.solaris Kralizec Craig <cd@lios.apana.org.au> wrote:
>> Hi everyone,
>> 
>> It's time for me to look at a new backup strategy and I'm considering a DLT
>> array managed with Amanda (from "http://www.amanda.org"), but some people
>> have suggested I shouldn't even bother with DLT and go straight to LTO
>> instead.
>> 
>> LTO arrays are a significant order or magnitude more expensive on average
>> than DLT arrays with 1 or more DLT-7000 drives in them, which is the main
>> reason I've been initially angling towards a good quality DLT array.
>> 
>> Anyway, what are the advantages and disadvantages of each type of backup
>> media? My backup requirements are not ultra-massive super-secret
>> government-type backup 'farms' in size, just a small array with enough
>> capability to reliabably provide data backup (and recovery) services for my
>> small network of around 10 or so active systems.
> 
> First of all, consider this: The DLT8000 manufacturing was stopped about
> a year ago. The DLT7000 sometime before that. These are seriously obsolete
> drives.

And probably not available for purchase.


> We've migrated from DLT700 and DLT8000 to LTO2. We found that the DLT7000
> was flakey, with at least one drive failing every month (out of 16 total).
> The DLT-8000 was decidedly better, but still failed more than expected.
> Curiously, we didn't have a lot of read errors with either media, but we
> also treated it fairly delicately.

What on earth where you doing to those DLT drives? I used a DLT7000
autochanger (HP 718) for two years doing full backups five times a week,
and never suffered a single problem. In fact I have only ever had a
DLT4000 drive give up the ghost on me and it was seriously old. I still
use a DLT7000 drive at home for doing backups without problems.

> 
> Conversely, I know of quite a few people who have had quite a lot of
> problems with the original LTO. I've never worked with it, but anecdotally
> I'd stay away. At the very least, I'd consider a SDLT 320, and if you can
> justify the price, an LTO2.
> 

Anyone any experience with SAIT1?

JAB.

-- 
Jonathan A. Buzzard                 Email: jonathan (at) buzzard.me.uk
Northumberland, United Kingdom.       Tel: +44 1661-832195

In article <d3d54p$ap1$1@yoda.apana.org.au>, Kralizec Craig wrote:
> Hi everyone,
> 
> It's time for me to look at a new backup strategy and I'm considering a DLT
> array managed with Amanda (from "http://www.amanda.org"), but some people
> have suggested I shouldn't even bother with DLT and go straight to LTO
> instead.

We use now LTO, i used DLT for many years from DLT2000 to DLT7000 and it
was very often full of problems:

 * read/write errors
 * lots of cleaning needed
 * problems with tape leader ( hangs out very often, we used DLT drives in
   a tape library and as consequence we had gripper crashes, because the
   gripper collides with the tape cartridge which was shaked out of the
   drive by vibrations )

using now LTO2 tapes with about 25 TB of active data, no failure nor read
errors. Ok we using it now for six months, but i think its much more
reliable than DLT.


Udo
-- 
+--------------------------------------------------------------------------+
| Udo Toedter | URZ        | Udo.Toedter@uni-jena.de | Phone +493641940532 |
|             | FSU Jena   |                         | FAX   +493641940632 |
+--------------------------------------------------------------------------+

Jonathan Buzzard wrote:

>On Mon, 11 Apr 2005 23:00:41 +0000, Colin B. wrote:
>
>  
>
>>In comp.unix.solaris Kralizec Craig <cd@lios.apana.org.au> wrote:
>>    
>>
>>>Hi everyone,
>>>
>>>It's time for me to look at a new backup strategy and I'm considering a DLT
>>>array managed with Amanda (from "http://www.amanda.org"), but some people
>>>have suggested I shouldn't even bother with DLT and go straight to LTO
>>>instead.
>>>
>>>LTO arrays are a significant order or magnitude more expensive on average
>>>than DLT arrays with 1 or more DLT-7000 drives in them, which is the main
>>>reason I've been initially angling towards a good quality DLT array.
>>>
>>>Anyway, what are the advantages and disadvantages of each type of backup
>>>media? My backup requirements are not ultra-massive super-secret
>>>government-type backup 'farms' in size, just a small array with enough
>>>capability to reliabably provide data backup (and recovery) services for my
>>>small network of around 10 or so active systems.
>>>      
>>>
>>First of all, consider this: The DLT8000 manufacturing was stopped about
>>a year ago. The DLT7000 sometime before that. These are seriously obsolete
>>drives.
>>    
>>
>
>And probably not available for purchase.
>
>
>  
>
>>We've migrated from DLT700 and DLT8000 to LTO2. We found that the DLT7000
>>was flakey, with at least one drive failing every month (out of 16 total).
>>The DLT-8000 was decidedly better, but still failed more than expected.
>>Curiously, we didn't have a lot of read errors with either media, but we
>>also treated it fairly delicately.
>>    
>>
>
>What on earth where you doing to those DLT drives? I used a DLT7000
>autochanger (HP 718) for two years doing full backups five times a week,
>and never suffered a single problem. In fact I have only ever had a
>DLT4000 drive give up the ghost on me and it was seriously old. I still
>use a DLT7000 drive at home for doing backups without problems.
>
>  
>
>>Conversely, I know of quite a few people who have had quite a lot of
>>problems with the original LTO. I've never worked with it, but anecdotally
>>I'd stay away. At the very least, I'd consider a SDLT 320, and if you can
>>justify the price, an LTO2.
>>
>>    
>>
>
>Anyone any experience with SAIT1?
>
>JAB.
>
>  
>
Did you ever try to read any of those DLT tapes you "never had a 
problem" with?
DLT heads wear and need repair or replacement fairly frequently.  My 
experience with DLT4000 and DLT7000 drives was that the heads would last 
about a year with if I wrote two or three tapes a day with them.  The 
symptom was that the drive would request a cleaning tape and, after 
being cleaned, would immediately request another cleaning tape!  Field 
service would swap out the drive and we would be good for another year.

Le Wed, 13 Apr 2005 12:50:30 +0000, Udo Toedter a �crit�:

> using now LTO2 tapes with about 25 TB of active data, no failure nor read
> errors. Ok we using it now for six months, but i think its much more
> reliable than DLT.

I agree strongly with that. DLT is coming to an end...

-- 
Si non confectus non reficiat.

In comp.unix.solaris Jonathan Buzzard <jonathan@uk.me.buzzard> wrote:
> On Mon, 11 Apr 2005 23:00:41 +0000, Colin B. wrote:
> 
>> First of all, consider this: The DLT8000 manufacturing was stopped about
>> a year ago. The DLT7000 sometime before that. These are seriously obsolete
>> drives.
> 
> And probably not available for purchase.

Certainly not new, but they're available refurbished all over the place.

>> We've migrated from DLT700 and DLT8000 to LTO2. We found that the DLT7000
>> was flakey, with at least one drive failing every month (out of 16 total).
>> The DLT-8000 was decidedly better, but still failed more than expected.
>> Curiously, we didn't have a lot of read errors with either media, but we
>> also treated it fairly delicately.
> 
> What on earth where you doing to those DLT drives? I used a DLT7000
> autochanger (HP 718) for two years doing full backups five times a week,
> and never suffered a single problem. In fact I have only ever had a
> DLT4000 drive give up the ghost on me and it was seriously old. I still
> use a DLT7000 drive at home for doing backups without problems.

Hmm. One drive a month with 16 total is a lifespan of well over a year,
which doesn't sound quite as bad. These things were typically running about
40% duty cycle, or ~10hr/day.

Leaders would get lost, that was easy to fix. Sometimes it would start
claiming that the heads needed cleaning, even right after cleaning had
been done. I'm told that's often a symptom of head wear, which I could
easily believe. However, we had another, odder problem on them. Once in
a while, the transfer rate would suddenly take a nosedive on a particular
drive. From steady state throughput of about 6-7MB/sec (we were limited by
the system, not the drives) it would suddenly drop to ~20kB/sec!!! We
confirmed that it wasn't the media, cleaned the heads, upgraded the firmware,
had about five different calls open with STK, and after half a year of
headscratching, nobody came up with an answer. The only solution was to
replace them.

Colin

Maybe a little of topic, but we are going to buy a new backup device, 
and the company is used to buy it from HP, they said it is compatible 
with Solaris (we make the backup with veritas).

But it is in the same family as DLT tape devices so I am worring reading 
this thread.

Any experiences with Ultrium (�?) tecnology?
( We are going to buy a HP StorageWorks autoloader Ultrium 460 )


Angel Cabello

I am sorry, I have just visit HP's web site and it shows clearly that 
this device is LTO.


Angel

angel wrote:
> Maybe a little of topic, but we are going to buy a new backup device, 
> and the company is used to buy it from HP, they said it is compatible 
> with Solaris (we make the backup with veritas).
> 
> But it is in the same family as DLT tape devices so I am worring reading 
> this thread.
> 
> Any experiences with Ultrium (�?) tecnology?
> ( We are going to buy a HP StorageWorks autoloader Ultrium 460 )
> 
> 
> Angel Cabello

On Wed, 13 Apr 2005 13:23:48 -0400, Richard B. Gilbert wrote:

[SNIP]
>
> Did you ever try to read any of those DLT tapes you "never had a 
> problem" with?
> DLT heads wear and need repair or replacement fairly frequently.  My 
> experience with DLT4000 and DLT7000 drives was that the heads would last 
> about a year with if I wrote two or three tapes a day with them.  The 
> symptom was that the drive would request a cleaning tape and, after 
> being cleaned, would immediately request another cleaning tape!  Field 
> service would swap out the drive and we would be good for another year.

The service life on a DLT4000 head is only 10,000 hours, which is a bit
over a year of continuous use. For a DLT7000 drive it is 30,000 hours
which is about 3.5" years.

I was writing 4 tapes a day, five days a week, with all to frequent
restores (it also backed up the client workstations which where running on
NT4 which would go south) without ever any problems.

The only DLT drive that has ever gone wrong on me was a DLT4000 drive and
it is nothing to do with the tape heads or anything. It powers up fine,
but is not seen on the SCSI bus :(

JAB.

-- 
Jonathan A. Buzzard                 Email: jonathan (at) buzzard.me.uk
Northumberland, United Kingdom.       Tel: +44 1661-832195

Kralizec Craig wrote:
> Hi everyone,
> 
> It's time for me to look at a new backup strategy and I'm considering a DLT
> array managed with Amanda (from "http://www.amanda.org"), but some people
> have suggested I shouldn't even bother with DLT and go straight to LTO
> instead.
> 
> LTO arrays are a significant order or magnitude more expensive on average
> than DLT arrays with 1 or more DLT-7000 drives in them, which is the main
> reason I've been initially angling towards a good quality DLT array.
> 
> Anyway, what are the advantages and disadvantages of each type of backup
> media? My backup requirements are not ultra-massive super-secret
> government-type backup 'farms' in size, just a small array with enough
> capability to reliabably provide data backup (and recovery) services for my
> small network of around 10 or so active systems.
> 
> Regards,
> 
> Craig.
> 
been servicing/using DLT since TK50 (95mb or was it 105mb).
      they broke the tape leader once a year. lots of debris !

      go for price, sdlt or lto2 are both very good.

/j�rgen

Kralizec Craig <cd@lios.apana.org.au> writes:

> Hi everyone,
>
> It's time for me to look at a new backup strategy and I'm considering a DLT
> array managed with Amanda (from "http://www.amanda.org"), but some people
> have suggested I shouldn't even bother with DLT and go straight to LTO
> instead.
>

Speaking of LTO2 and amanda, does anyone has a good tapetype for LTO2
tapes. I have seen quite a few different ones on the web, but don't know
what to choose.

TIA, Dragan

-- 
Dragan Cvetkovic, 

To be or not to be is true. G. Boole      No it isn't.  L. E. J. Brouwer

!!! Sender/From address is bogus. Use reply-to one !!!

Jonathan Buzzard <jonathan@uk.me.buzzard> writes:

>On Mon, 11 Apr 2005 23:00:41 +0000, Colin B. wrote:

>> First of all, consider this: The DLT8000 manufacturing was stopped about
>> a year ago. The DLT7000 sometime before that. These are seriously obsolete
>> drives.

>And probably not available for purchase.

It is rare to see new DLT-7000's around - I know that already.

>> We've migrated from DLT700 and DLT8000 to LTO2. We found that the DLT7000
>> was flakey, with at least one drive failing every month (out of 16 total).
>> The DLT-8000 was decidedly better, but still failed more than expected.
>> Curiously, we didn't have a lot of read errors with either media, but we
>> also treated it fairly delicately.

>What on earth where you doing to those DLT drives? I used a DLT7000
>autochanger (HP 718) for two years doing full backups five times a week,
>and never suffered a single problem. In fact I have only ever had a
>DLT4000 drive give up the ghost on me and it was seriously old. I still
>use a DLT7000 drive at home for doing backups without problems.

I've seen similar reports from backup installations that were designed
properly. I guess in multi-terrabyte backup situations where you have
robotic backup machines that take up entire rooms, drive failures will be a
frequent occurence, which is why those devices would have many drives
installed to cover for failures up to a certain tolerance.

My situation is nothing like that - a handful of systems running 24/7 which
need reliable, local data backup managed with, most likely, Amanda. These
systems are not part of any commercial operation so I am not locked into
using proprietry backup management software if I don't want to.

Regards,

Craig.
-- 
 SUN RIPENED KERNELS - Surplus Sun Microsystems Equipment, Parts + Accessories
    Waterfall, NSW, Australia - Operated by Craig Dewick - Founded in 1996
Main site: www.sunrk.com.au - Ebay Shop: www.ebayshops.com.au/sunripenedkernels
  Ph: +612-9520-2547 - Fax: +612-9520-2557 - Mobile: 04-2163-0547 (int. +614)

Dragan Cvetkovic <me@privacy.net> writes:

>Kralizec Craig <cd@lios.apana.org.au> writes:

>> Hi everyone,
>>
>> It's time for me to look at a new backup strategy and I'm considering a DLT
>> array managed with Amanda (from "http://www.amanda.org"), but some people
>> have suggested I shouldn't even bother with DLT and go straight to LTO
>> instead.

>Speaking of LTO2 and amanda, does anyone has a good tapetype for LTO2
>tapes. I have seen quite a few different ones on the web, but don't know
>what to choose.

Not sure what you could use, but the Amanda users mailing list has people
talking about using LTO tape drives very regularly. Go to the Amanda site at
"http://www.amanda.org" and subscribe to the 'amanda-users' mailing list.

Regards,

Craig.

-- 
 SUN RIPENED KERNELS - Surplus Sun Microsystems Equipment, Parts + Accessories
    Waterfall, NSW, Australia - Operated by Craig Dewick - Founded in 1996
Main site: www.sunrk.com.au - Ebay Shop: www.ebayshops.com.au/sunripenedkernels
  Ph: +612-9520-2547 - Fax: +612-9520-2557 - Mobile: 04-2163-0547 (int. +614)