Monday, 19 October 2009

Data loss

These days we are hearing more often about data loss events at the WLCG sites. Today it was the NL-T1 site that reported some data loss in the daily Operations meeting. Apparently, the tape drive loaded the tape and, instead of reading it, it just destroyed it. A similar event happened to us at PIC at the end of September, when we lost a tape containing 214 files from CMS. Nothing could be done with that piece of hardware... not even rewinding it! Luckily for us, all of those files were replicated in some other Tier-1 or at CERN, so we could fix the problem quite straightaway.
We were used to think in tapes as a safe media for data... but these episodes of tape destruction show that this is not always the case. A bit scary.
Anyhow, even ig it does not solve anything but it is nice to see that WLCG sites we are not the only ones losing data. Even Microsoft loses some data eventually!

1 comment:

joseflix said...

Yeah, we recovered the CMS files completely from CERN... HW can break at all the stages, after all and unfortunately... ;(