Table of Contents

Requirements

  • ACLs
  • Fault-tolerant RAID
  • 3+ Terabyte capacity
  • Data encryption
  • Data partitioning
  • User quotas

Secondary Requirements

Backup

Configuration

  • 4-8 Disk RAID6
    • dmcrypt
      • LVM

Linux >2.6.17 can resize RAID5

Data Partitioning

  • Inherits MediaCentre.BackEnd requirements
  • User data (/home)
  • Backup data (/systems)
  • Project data (/src)
  • Multimedia data (/media)
  • Fast access data (RAID0)

Filesystem

XFS

  • Very fast
  • ACLs
  • Not-resizeable

Both XFS and JFS are good candidates.

Benchmarking from 2004: http://linuxgazette.net/102/piszcz.html

"XFS is only safe when you have:

a) no write caching on the drive (barrier or nobarrier)
        b) non-volatile write caching on the drive (barrier or nobarrier)
        c) volatile write caching and barriers supported and enabled

The same conditions hold true for any filesystem that requires I/O ordering guarantees to maintain filesystem consistency…" - SGI Archive

Opinions on XFS vs JFS

XFS important options:

* mkfs.xfs -l size=128m (seems to be the default)
 * nobarrier?
 * noatime
 * block size <= page size  (Linux limit) (4k on x86_64)

RAID 5 tuning

EXT4

  • Resizeable
  • ACLs
  • Comparable performance to XFS, better metadata performance
  • Clear upgrade path to btrfs. (btrfs_convert)

Hardware

CPU Power

  • Buffalo TeraStation uses Freescale MPC8241 PPC @ 266MHz, 128MB RAM
    • TeraStation has Realtek 8110 ethernet, not Jumbo clean

Commercial NAS

Model Bays Price Link
       
Buffalo Terastation Pro 4 ~700  
Synology 407e 4 £380  
Infrant ReadyNAS NV+ 4 £500  
D-Link DNS-323 2 £150 froogle

Hardware Raid Adapters

Model Type Ports Price
       
Adaptec 2410SA SATA 4 £220
HighPoint RocketRAID 1640 SATA 4  
ICP Vortex 8546RZ SATA 4  
LSI MegaRAID 150-4 SATA 4  

Software Raid Adapters

Model Type Ports Price
       
Adaptec 1430SA PCI-E 4 £62
Promise SATA300 TX4 PCI-66 4 £55
Promise SATA300 TX4302 PCI-66 2, 2e £55

http://www.span.com/catalog/product_info.php?products_id=5090&source=gbaseuk&currency=GBP

eSATA adapters

Disk Enclosures

Hard Disks

Maxtor: 250=6.5, 320=6.8
WD: 320=5.9, 400=4.8, 500=6.4

Seagate: 400=5.47, 500=6.7 (ST3500641AS), 500=5.95

Model Buffer Capacity Price Warranty
         
Samsung HD501LJ 16 500 69 (Scan) 3
WD5000KS 16 500 80 (Misco) 3
Seagate 7200.10 ST3500630AS 16 500 OEM 87, Dabs 77 5 non-OEM

Notes

  • For connecting disk enclosures to external controller
    • eSATA (one per SATA channel)
    • Infiniband (one per 4 SATA channels)

SAS, eSATA, ML

Port Multipliers

Support from patched 2.6.22

RAID

Links

http://tweakers.net/reviews/557/29 - comparison of 9 SATA hardware raid cards
http://www.chemistry.wustl.edu/~gelb/castle_raid.html - software vs hardware raid (Linux)
http://www.hwb.no/artikkel/15307
http://www.smallnetbuilder.com/content/view/27840/77/ - build a cheap and fast raid 5 NAS
http://www.terastation.org/wiki/Hacking
http://www.terastation.org/wiki/Real_NAS
http://www.cooldrives.com/eidrrerasaii.html
http://www.span.com/ - Storage array cases
http://tomshardware.co.uk/2007/05/15/the_spring_hard_drive_guide_uk/
http://marc.info/?l=linux-raid&m=108225929401354&w=2 - thread on 3TB array
http://smartmontools.sourceforge.net/ - watching SMART for signs of failure
http://forums.anandtech.com/messageview.cfm?catid=27&threadid=2047740 - 3-5 TB raid
http://en.wikipedia.org/wiki/Lustre_%28file_system%29
http://www.gagme.com/greg/linux/raid-lvm.php - Linux LVM and RAID
[Tom's hardware - entry-level storage components review][60]
http://www.shimari.com/dm-crypt-on-raid/ - dmcrypt on RAID howto

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