Thank you for buying via links and ads on this site,
which earn me advertising fees or commissions.
As an Amazon Associate I earn from qualifying purchases.

Other World Computing...
B&H Photo...
Amazon
As an Amazon Associate I earn from qualifying purchases.
Memory Upgrades for 2019 Mac Pro - Save Up to 65% vs Factory Costs
877-865-7002
Today’s Deal Zone Items... Handpicked deals...
$2299 $1799
SAVE $500

$139 $89
SAVE $50

$3505 $2998
SAVE $507

$1099 $999
SAVE $100

$1099 $999
SAVE $100

$2797 $2497
SAVE $300

$1499 $1349
SAVE $150

$1499 $1299
SAVE $200

$2598 $2398
SAVE $200

$3998 $2998
SAVE $1000

$3498 $2998
SAVE $500

$1199 $1099
SAVE $100

$240 $175
SAVE $65

$1499 $1349
SAVE $150

$2799 $2499
SAVE $300

$7999 $6999
SAVE $1000

$250 $210
SAVE $40

$1199 $1099
SAVE $100

$799 $599
SAVE $200

$999 $949
SAVE $50

$1999 $1449
SAVE $550

$2799 $2499
SAVE $300

$449 $389
SAVE $60

$400 $270
SAVE $130

$1699 $999
SAVE $700

OWC Envoy Pro Elektron

Ultra-high performance across entire capacity, outperforms the competition.

Tiny, bus-powered, rugged, compact!


√ No more slow and noisy hard drives!

Real World Throughput for RAID-0 vs RAID-4 vs RAID-5

OWC Thunderbay Mini

See CPU Usage for RAID-0 vs RAID-4 or RAID-5.

But does it matter for real computing?

Understood properly, a 4-drive RAID-4 or RAID-5 is essentially a 3-drive RAID-0 stripe, plus parity.

So a perfect result would be equivalent performance to a 3-drive RAID-0 stripe.

Worst-case example

One ultra-efficient threaded application whose speed could be degraded by CPU usage of RAID-5 and RAID-4 is diglloydTools IntegrityChecker: with high data rates, RAID-4 or RAID-5 could compete for CPU cycles against the hashing computations.

OWC Envoy Express

World’s first Thunderbolt 3 M.2 NVME SSD enclosure.

Super fast, bus-powered, 3.3 oz, DIY easy, rugged and compact!


See also OWC Express 4M2
√ No more slow and noisy hard drives!

Results

The example below is also an artificial worst case: in real life files are generally not huge 32GB files (as here), and thus highly efficient to process, but a mix of many far smaller files. With many and smaller files, various other overheads become substantial relative to processing one huge file.

The graph below shows:

  • RAID-4 (dedicated parity drive) is definitely faster than RAID-5 (distributed parity), at least on SSDs.
  • RAID-4 as implemented by SoftRAID 5 is impressively efficient, delivering performance all but identical to a 3-drive RAID-0 stripe.

One cannot ask for better RAID-4 results than this. Moreover, these data rates far beyond what most programs can even begin to utilize.

Real world computing always involves some useful computation (not just reading or writing files). While the 4-drive RAID-0 stripe is 12% faster for hashing than the RAID-4, rare indeed are the computing tasks that can process over a gigabyte of data per second. Usage realities intrude: better to have fault tolerance at data rates that measure lower but have no significant impact on real world tasks.

disktester create-files --num-files 1 --file-size 32G
ic update

4 drives used for RAID-4 or RAID-5 and 3 or 4 drives for RAID-0 stripe

Write/read speed, plus hashing throughput with IntegrityChecker, RAID-0 vs RAID-4 vs RAID-5
OWC Envoy Pro EX SSD
Blazingly fast Thunderbolt 3 SSD!

Up to 4TB capacity, USB-C compatible.

USB-C model also available


Great for travel or for desktop!
OWC Accelsior 4M2 PCIe SSD
6000 MB/sec!
Mac or PC.


Ideal for Lightroom, Photoshop, video.
Capacity up to 16TB!
OWC Thunderblade Thunderbolt 3 SSD

Blazing fast, up to 16TB.

YEE HAH!



√ No more slow and noisy hard drives!
View all handpicked deals...

Datacolor SpyderCHECKR Color Chart and Calibration Tool for Digital Cameras
$139 $89
SAVE $50

diglloyd.com | Terms of Use | PRIVACY POLICY
Contact | About Lloyd Chambers | Consulting | Photo Tours
Mailing Lists | RSS Feeds | Twitter
Copyright © 2020 diglloyd Inc, all rights reserved.
Display info: __RETINA_INFO_STATUS__