[Beowulf] GPFS and failed metadata NSD

[Tim Cutts]

> On 25 May 2017, at 16:40, Prentice Bisbal <pbisbal at pppl.gov> wrote:
> 
> 
> On 05/21/2017 09:32 PM, Joe Landman wrote:
>> Third is "RAID is not a backup".
> 
> If I had a penny for every time I've had to explain this, including to other system admins!
> 
> Also, people also don't seem to understand that you need to backup regularly and to keep multiple backups from different dates.

Neither is replication a backup, and for the same reason.  However, at large data scales formal backups become prohibitively expensive, and therefore people use replication or erasure coding instead, and have to accept that while they're protected against hardware failure, they're not very well protected against user failure.

This is a really thorny issue.  On our archival storage platform for our raw sequencing data, where we use iRODS to manage the data, the data is replicated, and there are tight controls on who is allowed to modify the data (essentially, no-one - even the data owners are not allowed to modify or delete their own data on that platform; they have to make a specific request to a core team responsible for the archive)

Regards,

Tim




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