Asle,
Your message piqued my interest in the AIT so I decided to delve a little more deeply into the controversy. The Microsoft Word attachment was put together by Derek Gamradt of Dallas Digital (www.daldig.com) who is very knowledgeable about computer infrastructure issues. I have added notes in parenthesis to help clarify acronyms and to add my 2 cents worth.
-Steve gremban@ti.com
Tronrud, Asle EDNO wrote:
In Norway we agree with Mr. Alexei regarding support of the AIT streamer from SONY or Seagate (called Sidewinder for Seagate) on the filers.
It is correct that the DLT7000 (on the brochure) has the possibilities of slightly more sustained transfer the the AIT, but in real life the AIT slightly outperforms the DLT 7000 - and in addition the AIT's are 60% cheaper! In Norway the pricing at the moment is approximately DLT7000 85000 NOK and the AIT 35000 NOK. Big shock people wanting the AIT's.
The AIT's are using the most powerful compression algorithm in the market (ALDC developed by IBM). Compression ratio is in average 1:2.6, which gives in average approx. 65 GB on each media. DLT's and Mammoth in average 1.8 (Mr Gremban, TI below is reporting an average on appr. 1.7)
The sustained transfer is increasing to the same 1:2.6 ratio (7.8 MB/sec)
In addition the AIT has a Metal evaporation and Carbon coating on the media which makes the media even more robust (archival time on media guaranteed from SONY > 30 years)
Memory In Cassette (MIC) on the AIT makes the funniest difference:
Media Load Time 10 sec - DLT 45 sec. (4,5 times faster) Average File Access 23 sec - DLT 60/68 sec (3 times faster)
Regarding transfer rate, whether the AIT or the DLT7000 has any problems recieving the data from the NetApp filers because of the following:
Since most of the filers installed usually is containing thousands and millions of small files instead of a few big files - this (whether one likes it or not) leads to an significant decrease in backup throughput. This happens not only on NetApp filers, but on all kinds of machines serving files out there. The MB/min output number will anyway be lower than the number handled by the AIT and DLT.
So AIT is 60% cheaper, has 3-5 times faster access/media load time and arhival time in the media is more than 30 years. This is what is interesting to the customer base. You could buy two AIT streamers instead and place them both locally on the NetApp's - maybe this will do something with the numbers, I am not sure.
By the way, AIT-2 is coming in the autumn this year. 130GB capacity and transfer rate 12MB/s compressed.
Please support the AIT's!
Rgds Asle Tronrud _______________________________________________________
Asle Tronrud Sales Engineer Storage
Berendsen Data Tel. +47 2208 8500 Div. av Berendsen Components AS Dir. +47 2208 8569 Konows gt. 8 Fax. +47 2208 8595 P.O.Box 9376, Groenland Mob. +47 9001 2906 N-0135 Oslo, Norway Email: aslet@berendsen.no http://www.berendsen.no _______________________________________________________
-----Opprinnelig melding----- Fra: Bjørnsen, Paal H. EDNO Sendt: 13. februar 1998 09:19 Til: Tronrud, Asle EDNO Emne: VS: AIT vs. DLT7000
-----Opprinnelig melding----- Fra: Steve Gremban [SMTP:gremban@msp.sc.ti.com] Sendt: 13. februar 1998 07:39 Til: toasters@mathworks.com Emne: AIT vs. DLT7000
Alexei,
We are using DLT7000 (5-10 MB/sec depending on compression) drives which actually outperform the Sony AIT (3-7.8 MB/sec depending on compression). We are not quite seeing 2:1 compression, we get about 60GB compressed on each 35GB tape.
-Steve Gremban gremban@ti.com
Previous message follows:
I would like to see AIT supported; we currently use DLT, but as our backup needs are approaching 300GB (well, as soon as I get my new filer), DLT is not cutting it (backup/restore times are too long). Also, the media is a huge problem (DLT's are not all too happy with a drop...).
I suspect that these additional drives will be supported eventually.
Alexei