Veritas-bu

[Veritas-bu] Where in NBU are drive settings (LTO-1 and LTO-2 ) tuned separatel y?

2003-12-05 18:33:31
Subject: [Veritas-bu] Where in NBU are drive settings (LTO-1 and LTO-2 ) tuned separatel y?
From: Joost Mulders <mail AT j-mulders.demon DOT nl> (Joost Mulders)
Date: Sat, 6 Dec 2003 00:33:31 +0100 (CET)
Hi Aren, 

No, you don't need to install two different drivers for the LTO[12] tapedrives. 

You have LTO1 and LTO2 drives in your ADIC lib., right?

There are LT01 and LTO2 cartridges (tapes) on the market. LTO2 drives CAN write 
LTO1 cartridges, but with a "limited" speed of 20MB/s. To get 30 (or 35) MB/s 
in 
an LTO2 drive, you need to use LTO2 tapes in it. If you purchased your tapes 
from IBM: LTO1 cartridges are black and LTO2 cartridges are purple. 


Best regards, Joost


>Hello Joost,
>What do you mean by "LTO1 media"? We use the atdd driver, ver 3.1.0.3 GES
>IBM magstar ultrium tape device driver, the devices show "CLAIMED" on ioscan
>to all of the LTO (1 & 2)devices with this software, are you telling me that
>with HP-UX you must install two separate drivers and bind each by hand?  



>-----Original Message-----
>From: Joost Mulders [mailto:mail AT j-mulders.demon DOT nl] 
>Sent: Friday, December 05, 2003 1:09 PM
>To: veritas-bu AT mailman.eng.auburn DOT edu; Aren.Parisi AT wwireless DOT com
>Subject: Re: [Veritas-bu] Where in NBU are drive settings (LTO-1 and LTO-2)
>tuned separatel y?
>
>
>Hi Aren, 
>
>Two notes on your question:
>
>1. Media
>Make sure you are using LTO2 media in your LT02 drives. With IBM drives (and
>I 
>think the others as well), using LTO1 media in an LTO2 drives reduces the
>max. 
>throughput to 20MB/s. 
>
>2. SIZE_DATA_BUFFERS
>Make sure you have /usr/openv/netbackup/db/config/SIZE_DATA_BUFFERS file on
>your 
>media server(s) with a value of 262144 (256K) in it. This file controls the
>size 
>of the data buffers yadiyadiyadi, but also the blocksize used to transfer
>data 
>to the drive. Using "big blocks" lowers SCSI/FC bus overhead (each block has
>to 
>be sent and acknowledged) and it improves the efficency of the compression 
>algorithm in the drive: the larger the block, the more "similar" patterns
>can be 
>found and compressed.
>
>The above is true for all tapedrives. There are no LTO2 specific knobs.
>
>joost
>
>
>>NBU 3.4.1 Master:HP-UX 11i three-way service guard cluster Library:ADIC 
>>scalar10k IBM Ultrium drives:[email protected], [email protected] same cabinet. We have 
>>just benchmarked our new LTO-2 drives and they are NO FASTER than the 
>>LTO-1 drives. Are there separate tuneables for the new drives we are 
>>not looking at?  Buffer settings, something undocumented perhaps?  We 
>>have a 3GB (bound) FC ethernet connection on the media server so I 
>>don't think it's a network bottleneck, disk is XP-512 (rebadged 
>>Hitachi) screaming fast disk.  Tested same class on each type of drive, 
>>identical runtimes. ??? Thank you experts.
>>
>>     Aren M. Parisi *
>> Information Technology
>>  Western Wireless Corp.
>>(425)313-5225 mob.(206)795-6631
>> Where are we going and why am I in this handbasket?
>>
>
>-- 
>Long may you run.

-- 
Long may you run.