We are in the process of planning to replace our 550 LPAR server. One of the proposals from our service provider is to update our Tape technology from LTO2 to LTO4. Over the past years we have had a lot of issues with the LTO2 technologies. Tape drive errors were IBM replaced the drive (some times numerous times). Media errors on the LTO2 tape cartridge (even though usage never was high for the number of times the cartridge was written to 50-60 times tops). Has any one in this forum gone to this technology and what is your experience (Hardware reliability, tape cartridge issues)?
Doreen, have you now moved to LTO4's? We have switched but are not seeing the reduction in backup up times as was advertised 2x to 5 x faster than LTO2's. We are working with our bussiness partner as to why we are not seeing this decrease in backup time.
The possible problems with those "fast tapes" can be:
- can your I/O system read the data fast enough to bring the tape into "stream" mode (120 MB/sec) and keep it there? If not, then the tape will go in stop/start mode - which is probably slower than with LTO2/LTO3 and will mechanically draw a lot
- is the bus the SCSI/HBA is plugged to fast enough to serve this?
- are there any big jobs running when you´re doing online backups that will take the necessary I/O?
- if you use network to backup, is it fast enough (1 GBit Ethernet is not sufficient, 125 MB/sec theoretical max.)
If you have more than one tape you backup in parallel then those number need to be doubled.
We haven´t switched yet to LTO4 since our infrastructure does not provide enough "power" to serve those tapes completely (we would need to go to Infiniband or 10 Gbit)
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