[gpfsug-discuss] Strategies - servers with local SAS disks

[Uwe Falke]

I have once set up a small system with just a few SSDs in two NSD servers, 
providin a scratch file system in a computing cluster.
No RAID, two replica. 
works, as long the admins do not do silly things (like rebooting servers 
in sequence without checking for disks being up in between). 
Going for RAIDs without GPFS replication protects you against single disk 
failures, but you're lost if just one of your NSD servers goes off.

FPO makes sense only sense IMHO if your NSD servers are also processing 
the data (and then you need to control that somehow). 

Other ideas? what else can you do with GPFS and local disks than what you 
considered? I suppose nothing reasonable ...

 
Mit freundlichen Grüßen / Kind regards

 
Dr. Uwe Falke
 
IT Specialist
High Performance Computing Services / Integrated Technology Services / 
Data Center Services
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E-Mail: uwefalke at de.ibm.com
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From:   "Oesterlin, Robert" <Robert.Oesterlin at nuance.com>
To:     gpfsug main discussion list <gpfsug-discuss at spectrumscale.org>
Date:   11/30/2016 03:34 PM
Subject:        [gpfsug-discuss] Strategies - servers with local SAS disks
Sent by:        gpfsug-discuss-bounces at spectrumscale.org



Looking for feedback/strategies in setting up several GPFS servers with 
local SAS. They would all be part of the same file system. The systems are 
all similar in configuration - 70 4TB drives. 
 
Options I?m considering:
 
- Create RAID arrays of the disks on each server (worried about the RAID 
rebuild time when a drive fails with 4, 6, 8TB drives)
- No RAID with 2 replicas, single drive per NSD. When a drive fails, 
recreate the NSD ? but then I need to fix up the data replication via 
restripe
- FPO ? with multiple failure groups -  letting the system manage replica 
placement and then have GPFS due the restripe on disk failure 
automatically
 
Comments or other ideas welcome.
 
Bob Oesterlin
Sr Principal Storage Engineer, Nuance
507-269-0413
 
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