Hi! I saw some related information (source:Quantum) under http://www.datastor.co.nz/Datastor/Promotions.nsf/4a91ca5e06d20e15cc256ebe0002290e/d954d1c5e5e6df09cc25723b00740956/$FILE/When%20to%20Choose%20LTO3%20Tape%20Drives.pdf
best Juraj > -----Ursprüngliche Nachricht----- > Von: ADSM: Dist Stor Manager [mailto:[EMAIL PROTECTED] Im > Auftrag von Henrik Wahlstedt > Gesendet: Donnerstag, 21. Dezember 2006 15:43 > An: ADSM-L@VM.MARIST.EDU > Betreff: Re: Performance with move data and LTO3 > > Nice one! I get back on this after the Holidays. > > Thanks > Henrik > > -----Original Message----- > From: ADSM: Dist Stor Manager [mailto:[EMAIL PROTECTED] > On Behalf Of Prather, Wanda > Sent: den 19 december 2006 18:15 > To: ADSM-L@VM.MARIST.EDU > Subject: Re: Performance with move data and LTO3 > > Interesting. > > Differences in IBM vs. HP LTO3 drives: > > I have been told that the IBM drives do "smart" > compression using a bypass buffer. If a block of data is > going to expand during compression, the IBM drives will stop > compression and write the uncompressed block, which should > make them a bit faster. > > Re tape to tape operations: > > I have observed the same behavior; tape to tape operations > are inexplicably slower than you would expect when the TSM > server is on WINDOWS. I have observed this with fibre > drives, and SCSI drives, 3590 and LTO. I suspect it has > something to do with buffer use, but since Windows provides > no tools whatever to measure performance of tape devices or > buses with tapes on them, I've never been able to make any > other determination. > > I don't think it is a READ issue with the drives. Try > testing using an AUDIT; that just reads the tape and doesn't > write anything. I suspect you'll get faster READ times. I > would be interested in seeing your results! > > > > Wanda Prather > "I/O, I/O, It's all about I/O" -(me) > > > > > -----Original Message----- > From: ADSM: Dist Stor Manager [mailto:[EMAIL PROTECTED] > On Behalf Of Henrik Wahlstedt > Sent: Thursday, December 14, 2006 10:37 AM > To: ADSM-L@VM.MARIST.EDU > Subject: Performance with move data and LTO3 > > Hi, > > I wonder what transfer rates (move data from drive to drive) > I am supposed to see with LTO3. > > I have two TSM servers, one 32-bit Win2k3 and one 64-bit > 2.6.9-11.Elsmp, with a SL500 and FC LTO3 drives. > Similar HW (HP DL585) except for one server have HP- and the > other have IBM drives. Drives are on separate PCI busses. > > I used a dataset of 50Gb with large files, same file type on > both systems. Only scratch tapes and no expiration on the datasets. > No other tape activity on the systems during the tests. > > I tested disk->mt0->mt1->mt2->mt3->mt1->mt0->disk > From disk to tape I get a throughput of 74-76Mb/s with IBM > drives, (migration). > From tape to tape, (move data), with HP drives I get a > throughput of 30-46Mb/s and with IBM drives I get 39-59Mb/s. > From disk to tape, (move data), with IBM drives I get a > throughput of 44Mb/s. > > Apperently write speed seems OK but read spead is an issue?! > Or is this normal? > > > > Thanks > Henrik > > > > > > > > > > > > > > > > > > > > > ------------------------------------------------------------------- > The information contained in this message may be CONFIDENTIAL > and is intended for the addressee only. Any unauthorised use, > dissemination of the information or copying of this message > is prohibited. If you are not the addressee, please notify > the sender immediately by return e-mail and delete this message. > Thank you. > > > ------------------------------------------------------------------- > The information contained in this message may be CONFIDENTIAL > and is intended for the addressee only. Any unauthorised use, > dissemination of the information or copying of this message > is prohibited. If you are not the addressee, please notify > the sender immediately by return e-mail and delete this message. > Thank you. > Diese E-Mail enthält vertrauliche und/oder rechtlich geschützte Informationen. Wenn Sie nicht der richtige Adressat sind oder diese E-Mail irrtümlich erhalten haben, informieren Sie bitte sofort den Absender und vernichten Sie diese Mail. Das unerlaubte Kopieren sowie die unbefugte Weitergabe dieser Mail ist nicht gestattet. This e-mail may contain confidential and/or privileged information. If you are not the intended recipient (or have received this e-mail in error) please notify the sender immediately and destroy this e-mail. Any unauthorised copying, disclosure or distribution of the material in this e-mail is strictly forbidden.