L180 Library w/ LTO2 Drives - Cleaning Frequency? 1

[johngiggs]

I have auto clean disabled on my STK L180 library. I am running NetBackup Data Center 3.4 and I would like to set it up to clean the drives every so often, but I'm not sure how frequently the drives should be cleaned. After how many hours of drive time should the drives be cleaned? During the weekend a few of the drives are hit pretty hard and are running constantly for about 48 hours. Any help would be greatly appreciated.

Thanks,

John

 

[tapedrivedoctor]

John

my advice would be to enable autoclean. None of the manufacturers of LTO really give an indication of how often to clean the drive, They advise to clean when the drive requests to be cleaned. Cleaning tapes are abrasive and wear head life so I would clean as little as is necessary.

 

[tapechap]

The first introduction, originally the three LTO suppliers, HP, Seagate (Certance) and IBM, it was thought that tape drive cleaning would not be necessary because of the product specifications in the LTO environment. These same assumptions were made in the past with the 3480 tape drive series of products by IBM also Each LTO tape driver manufacturer originally approved compliance to just the form factor of the cartridge and other physical parameters.

Originally, the LTO consortium did not, intentionally, provide strict guidelines that controlled the quality of the media inside the cartridge. The only guideline at that time was just the length of the tape. The reason for this was that the consortium did not want to restrict the "open system" market. As a result of this, the quality of media being manufactured by various vendors has flucuated from the quality that was used during the original develop efforts by the tape drive manufacturers. So as time has gone by more tier 2 and 3 media suppliers have entered the market so that the range of the tape quality has broadened from the original few used for development. This fact, along with urging from STK has caused the drive suppliers to rethink their view on cleaning tape usage and procedure.

Competition between LTO suppliers is very intense and because of this they are very reluctant to formally publicize anything that could construe weakness in their drives. Thus formal announcements are unlikely from them, as they fear this could potentially be used by a competitor. New IBM LTO code will allow selection of a new formula to trigger cleaning. The new interval will send a clean message for the equivalent of 40 full cartridge passes. This will apply to IBM G1 (released) and G2 (pending) drives. Certance Corp will change their cleaning formula to trigger a clean message for every 100 tape motion hours. This is roughly equal to 50 full cartridge passes. HP LTO cleaning is triggered by error conditions. STK has not been informed of any changes to HP LTO’s at this time along these same lines.
StorageTek is seeing this as a positive step in keeping the media and drives as clean as possible which will lead to improved performance.

STK has been recommending cleaning since last year due to investigation into issues that they have seen at customer sites. The frequency of once a week is sufficient in normal usage accounts.

The only area of concern is the interaction of a library autocleaning cycle with Veritas, Legato, etc. Timers might need updating to allow the cleaning process without downing drives. Veritas has stated that they support Autocleaning on our libraries, but it is recommended that each vendor be consulted to assure what is needed by the application to enable its proper usage.

New IBM LTO Gen 1 drive code for STK has a bit that needs to be set to enable the drive to request cleaning to the library after the 40 mounts listed above (autoclean on the library on). Unfortunately, it takes a special program they have to go in and enable the bit once the code is installed. However, the new code for the Gen 1 drives is something that should be pursued at all costs it has 275+ fixes in it. Also, from reports, you had better be cleaning the IBM Gen 1 LTO drives with the frequency recommended above or eventual problems will start occurring. The IBM Gen 2 drives however does not have the cleaning bit included yet and not projected until 1Q05 release.

 

[johngiggs]

tapechap,

Thank you for the useful info!! Have a star!!

John

 

[Pachtva]

Hi..

The STk tape drives put a sense SCSI code into the SCSI BUS, this sense code its recognized by the software and active the clean status.