Re: I don't think she can hold much more Captain! She's gonna blow! (IBM LTO Tape)
Jim, We see the same phenomenon with Oracle table files. We backup those files to 7 GB Magstar XL tapes, but the tape drive compresses the files to fit as much as 24 GB on one tape. It actually put 32 GB once! By contrast, the same drives compress our Domino data to fit 8.5 GB on a 7 GB tape. The difference is that the Oracle files are largely empty space so they compress down to almost nothing. You'll see it reflected when you do reclamation. We reclaim two tapes containing 20+ GB of mostly Oracle data and the good data fills two tapes which report full at about 10 GB. Until I understood what was happening I though *SM was trying to corner the market in fuzzy logic. Tab Trepagnier TSM Administrator Laitram Corporation
Re: I don't think she can hold much more Captain! She's gonna blow! (IBM LTO Tape)
I have seen exactly the same type of results. One of my customers routinely gets 250+GB per tape; and in one other instance my customer got 400+GB, similar to what you are experiencing. Compression results are a function of the type of data. If you are using collocation, the compressability becomes more obvious for the type of data because a given node is clustered on a cartridge. For example if your clients compress their data, you will find tape capacities much closer to 100GB. In my case, the 400+ GB client was an API database client that sent very compressable data. Remember that the total amount of data written to the tape only shows up when the tape is marked full. When it is filling, TSM will keep on writing to the tape and you will see the Estimated Capacity increase. Joerg Pohlmann Jim Taylor [EMAIL PROTECTED]@VM.MARIST.EDU on 2001-08-28 15:47:29 Please respond to ADSM: Dist Stor Manager [EMAIL PROTECTED] Sent by: ADSM: Dist Stor Manager [EMAIL PROTECTED] To: [EMAIL PROTECTED] cc: Subject: I don't think she can hold much more Captain! She's gonna blow! (IBM LTO Tape) How much can these 100GB native tapes hold? Can I really be getting this kind of compression? Half a TB on one tape? Anyone else seeing this? My real issue is with the Status. It says that the tape is still filling, yet its Pct Util is only at 95%. I don't get this. I thought that a tape get to 100% full and the Est Cap keeps increasing until EOT is met. At which time the Status changes to Full and the Pct Util can then drop from 100% as the data on the tape expires. Have I been wrong??? tsm: TSM-D2q vol Volume Name Storage Device EstimatedPct Volume Pool NameClass Name Capacity Util Status (MB) --- -- - - /tsm/tsmstg/disk-vol01DISKPOOL DISK 5,000.0 30.5 On-Line A0TAPEPOOL LTOTAPE 100,000.07.2 Filling A7TAPEPOOL LTOTAPE 204,800.02.6 Filling A00023TAPEPOOL LTOTAPE 384,482.9 65.0Full A00031TAPEPOOL LTOTAPE 398,471.2 64.4Full A00035TAPEPOOL LTOTAPE 537,664.2 85.3 Filling tsm: TSM-D2 Jim Taylor Senior Associate, Technical Services Enlogix * E-mail: [EMAIL PROTECTED] * Office: (416) 496-5264 ext. 286 * Cell: (416)458-6802 * Fax: (416) 496-5245
I don't think she can hold much more Captain! She's gonna blow! (IBM LTO Tape)
How much can these 100GB native tapes hold? Can I really be getting this kind of compression? Half a TB on one tape? Anyone else seeing this? My real issue is with the Status. It says that the tape is still filling, yet its Pct Util is only at 95%. I don't get this. I thought that a tape get to 100% full and the Est Cap keeps increasing until EOT is met. At which time the Status changes to Full and the Pct Util can then drop from 100% as the data on the tape expires. Have I been wrong??? tsm: TSM-D2q vol Volume Name Storage Device EstimatedPct Volume Pool NameClass Name Capacity Util Status (MB) --- -- - - /tsm/tsmstg/disk-vol01DISKPOOL DISK 5,000.0 30.5 On-Line A0TAPEPOOL LTOTAPE 100,000.07.2 Filling A7TAPEPOOL LTOTAPE 204,800.02.6 Filling A00023TAPEPOOL LTOTAPE 384,482.9 65.0Full A00031TAPEPOOL LTOTAPE 398,471.2 64.4Full A00035TAPEPOOL LTOTAPE 537,664.2 85.3 Filling tsm: TSM-D2 Jim Taylor Senior Associate, Technical Services Enlogix * E-mail: [EMAIL PROTECTED] * Office: (416) 496-5264 ext. 286 * Cell: (416)458-6802 * Fax: (416) 496-5245
Re: I don't think she can hold much more Captain! She's gonna blow!(IBM LTO Tape)
I am not familiar with your tape units but when I started using Exabyte Mammoth2 scsi drives and tapes, 60gb native, 150gb compressed I saw exactly the same thing. Then the hammer dropped! I started getting some fsr (forward search record) errors. In compressed mode the tapes were able to hold more blocks of data than the the scsi command set could count in it's 3 byte counter. My data was being lost along the way. The problem is now documented and will be fixed in a future release. The only work around was to use non-compressed format. In my case, format is M2 instead of M2C. If this is also your problem you need to correct it pronto because your tpe storage pool is losing client data! Jim Taylor wrote: How much can these 100GB native tapes hold? Can I really be getting this kind of compression? Half a TB on one tape? Anyone else seeing this? My real issue is with the Status. It says that the tape is still filling, yet its Pct Util is only at 95%. I don't get this. I thought that a tape get to 100% full and the Est Cap keeps increasing until EOT is met. At which time the Status changes to Full and the Pct Util can then drop from 100% as the data on the tape expires. Have I been wrong??? tsm: TSM-D2q vol Volume Name Storage Device EstimatedPct Volume Pool NameClass Name Capacity Util Status (MB) --- -- - - /tsm/tsmstg/disk-vol01DISKPOOL DISK 5,000.0 30.5 On-Line A0TAPEPOOL LTOTAPE 100,000.07.2 Filling A7TAPEPOOL LTOTAPE 204,800.02.6 Filling A00023TAPEPOOL LTOTAPE 384,482.9 65.0Full A00031TAPEPOOL LTOTAPE 398,471.2 64.4Full A00035TAPEPOOL LTOTAPE 537,664.2 85.3 Filling tsm: TSM-D2 Jim Taylor Senior Associate, Technical Services Enlogix * E-mail: [EMAIL PROTECTED] * Office: (416) 496-5264 ext. 286 * Cell: (416)458-6802 * Fax: (416) 496-5245 -- Steve Bennett, (907) 465-5783 State of Alaska, Information Technology Group, Technical Services Section
Re: I don't think she can hold much more Captain! She's gonna blow! (IBM LTO Tape)
Can I have some of your data please? Don't let marketing get a hold of this! Kelly J. Lipp Storage Solutions Specialists, Inc. PO Box 51313 Colorado Springs CO 80949-1313 (719) 531-5926 Fax: (240) 539-7175 Email: [EMAIL PROTECTED] or [EMAIL PROTECTED] www.storsol.com www.storserver.com -Original Message- From: ADSM: Dist Stor Manager [mailto:[EMAIL PROTECTED]]On Behalf Of Joerg Pohlmann/CanWest/IBM Sent: Tuesday, August 28, 2001 5:02 PM To: [EMAIL PROTECTED] Subject: Re: I don't think she can hold much more Captain! She's gonna blow! (IBM LTO Tape) I have seen exactly the same type of results. One of my customers routinely gets 250+GB per tape; and in one other instance my customer got 400+GB, similar to what you are experiencing. Compression results are a function of the type of data. If you are using collocation, the compressability becomes more obvious for the type of data because a given node is clustered on a cartridge. For example if your clients compress their data, you will find tape capacities much closer to 100GB. In my case, the 400+ GB client was an API database client that sent very compressable data. Remember that the total amount of data written to the tape only shows up when the tape is marked full. When it is filling, TSM will keep on writing to the tape and you will see the Estimated Capacity increase. Joerg Pohlmann Jim Taylor [EMAIL PROTECTED]@VM.MARIST.EDU on 2001-08-28 15:47:29 Please respond to ADSM: Dist Stor Manager [EMAIL PROTECTED] Sent by: ADSM: Dist Stor Manager [EMAIL PROTECTED] To: [EMAIL PROTECTED] cc: Subject: I don't think she can hold much more Captain! She's gonna blow! (IBM LTO Tape) How much can these 100GB native tapes hold? Can I really be getting this kind of compression? Half a TB on one tape? Anyone else seeing this? My real issue is with the Status. It says that the tape is still filling, yet its Pct Util is only at 95%. I don't get this. I thought that a tape get to 100% full and the Est Cap keeps increasing until EOT is met. At which time the Status changes to Full and the Pct Util can then drop from 100% as the data on the tape expires. Have I been wrong??? tsm: TSM-D2q vol Volume Name Storage Device EstimatedPct Volume Pool NameClass Name Capacity Util Status (MB) --- -- - - /tsm/tsmstg/disk-vol01DISKPOOL DISK 5,000.0 30.5 On-Line A0TAPEPOOL LTOTAPE 100,000.07.2 Filling A7TAPEPOOL LTOTAPE 204,800.02.6 Filling A00023TAPEPOOL LTOTAPE 384,482.9 65.0Full A00031TAPEPOOL LTOTAPE 398,471.2 64.4Full A00035TAPEPOOL LTOTAPE 537,664.2 85.3 Filling tsm: TSM-D2 Jim Taylor Senior Associate, Technical Services Enlogix * E-mail: [EMAIL PROTECTED] * Office: (416) 496-5264 ext. 286 * Cell: (416)458-6802 * Fax: (416) 496-5245
