[Discuss] Dev Ops - architecture (local not cloud)

[blu at nedharvey.com (Edward Ned Harvey (blu))]

> From: discuss-bounces+blu=nedharvey.com at blu.org [mailto:discuss-
> bounces+blu=nedharvey.com at blu.org] On Behalf Of Derek Martin
> 
> Now, these days, it's actually hard to buy a disk
> that won't give you more than 8MB/s sustained transfer rate (which is
> roughly what you could expect over 100Mb network).  But Gigabit networks
> are common now, and if your NFS server is built for it (i.e. it isn't just yet
> another desktop with a single local disk) you should easily be able to far
> exceed the performance of a workstation's cheap local disk.

I've done a lot of benchmarking over the last decade, and I'll say this:

All disks perform approx 1.0 Gbit/sec sustained transfer.  This is true regardless of rpm's, regardless SAS or SATA, and even for SSD's.  The highest performance enterprise disks sometimes do around 1.2, but even the cheapest commodity SATA 5400 RPM disks sustain 1.0.

So even a single commodity disk can max out a 1 Gbit ethernet connection.

I am perfectly aware that many SSD's advertise themselves as sustaining 500MB/sec (4 Gbit) but in practice, it's completely hogwash.  

So, given a single 1Gbit ethernet connection, you will NOT exceed the performance of a single local disk, regardless of how great the storage array is at the other end of the ethernet cable.  However, there do exist much faster and more efficient buses out there - Fiber Channel, Infiniband, 10GigE, and SAS, which are able to carry several (or even several dozen) fully utilized disks worth of performance.  So your storage network architecture definitely makes a big difference.  As does your RAID topology, and your decision to use hard/soft raid, and everything else you can think of.