DSM-G600, DNS-3xx and NSA-220 Hack Forum

I have to admit, I am seriously concerned about the number of posts I have come across here where folks use RAID0 and then are looking for ways to retrieve lost data.

Does no-one take the time to research what they plan to do before they do it?

RAID0 has only one advantage - access speed - and on this hardware, I believe that is a theoretical advantage.  It's disadvantage is the increased probability of data loss.

NEVER - EVER - store data that you cannot afford to lose on a RAID0 array.

I'm inclined to say NEVER - EVER - store data on a RAID0 array, but I figure someone's going to ask why bother having one - good question - and here's one answer - using a RAID0 array (as compared to using a single disk of the same total capacity) can reduce the rendering time of certain graphic development tools significantly.

RAID0 arrays achieve their speed advantage by striping the data across the disks - in a two disk array, half your data is on one disk and half on the other, lose either disk and you lose it all.

index monkey wrote:

Wizard, you should be ashamed of yourself, kindy refer to "fordem" before making decisions about what is best for you where RAID is concerned. He diligently posts the minutiae concerning RAID all over this forum. NEVER - EVER dont research it at all. goodness gracious me, I wish everyone knew all about RAID and how it should be used for backup 

Dinna get your knickers in a twist - if only one person reads that post and learns from it, it's served it's purpose.

index monkey wrote:

Wizard, you should be ashamed of yourself, kindy refer to "fordem" before making decisions about what is best for you where RAID is concerned. He diligently posts the minutiae concerning RAID all over this forum. NEVER - EVER dont research it at all. goodness gracious me, I wish everyone knew all about RAID and how it should be used for backup 

Ok i made the wrong choice. I will use it with 2 disks without RAID.

Do you think i will search in every forum for the poor RAID implementation of this box before i buy it ? I bought this 323, it has to work correctly.
But what about using RAID1 when you can lose all your data just when you upgrade the firmware and the resync doesn't work?

D-Link think we are beta users and with all the work done is this forum, i hope they will be able to fix all these issues ...

It seems that RAID sotware on the 323 is not reliable enough ... Every time the firmware is updated the linux kernel is updated too ... strange.
I have a RAID0 on my pc and no problem with it (hardware raid0 ... makes all the difference and no need to boot on the eprom to fix a conf file)

Wizard wrote:

Ok i made the wrong choice. I will use it with 2 disks without RAID.

Do you think i will search in every forum for the poor RAID implementation of this box before i buy it ? I bought this 323, it has to work correctly.
But what about using RAID1 when you can lose all your data just when you upgrade the firmware and the resync doesn't work?

D-Link think we are beta users and with all the work done is this forum, i hope they will be able to fix all these issues ...

It seems that RAID sotware on the 323 is not reliable enough ... Every time the firmware is updated the linux kernel is updated too ... strange.
I have a RAID0 on my pc and no problem with it (hardware raid0 ... makes all the difference and no need to boot on the eprom to fix a conf file)

This has nothing to do with D-Link - this has nothing to do with the DNS-323 - it is simply how RAID0 works - ALL RAID0 arrays put your data at risk - and that includes the one in your PC.

You think you have hardware RAID on your PC - I'm willing to bet you don't - not unless you're running a server grade system.  The reality is that the majority of desktop systems out there that offer RAID, only offer RAID0 & RAID1, and do so using the system processor - if there is no dedicated RAID processor and XOR then it's not hardware RAID - the writes are being handled by the disk controller drivers and the system processor is doing the slicing & dicing.  Post the make & model of your motherboard and I'll show you the details.

For what it's worth - I have not yet lost data upgrading my firmware - and all of my resyncs have worked and believe me - I have pretty much put my DNS-323 through the wringer when it comes to it's RAID capabilities.

One more thing - this NAS server, like many low cost NAS servers, runs embedded linux.  The firmware IS linux - the only reason for updating the firmware is to update the linux "distro" (I use that term loosely) so why should it be so strange that updating the firmware also updates the kernel?

Wizard wrote:

Does no-one take the time to research what they plan to do before they do it?
I cannot afford a RAID5 big box ...

What does RAID5 have to do with anything?  It's not an option on this box - and every piece of hardware I've seen offer RAID5 has also offered RAID0 & RAID1 as options.

You've already admitted making a bad choice - D-Link wasn't responsible for that choice, they give you the options, you made the choice - if you bought a box that offered RAID5, who's to say you wouldn't have made the same bad choice.  It's easy to do - every other option reduces your storage capacity.

fordem wrote:

Wizard wrote:

Ok i made the wrong choice. I will use it with 2 disks without RAID.

Do you think i will search in every forum for the poor RAID implementation of this box before i buy it ? I bought this 323, it has to work correctly.
But what about using RAID1 when you can lose all your data just when you upgrade the firmware and the resync doesn't work?

D-Link think we are beta users and with all the work done is this forum, i hope they will be able to fix all these issues ...

It seems that RAID sotware on the 323 is not reliable enough ... Every time the firmware is updated the linux kernel is updated too ... strange.
I have a RAID0 on my pc and no problem with it (hardware raid0 ... makes all the difference and no need to boot on the eprom to fix a conf file)

This has nothing to do with D-Link - this has nothing to do with the DNS-323 - it is simply how RAID0 works - ALL RAID0 arrays put your data at risk - and that includes the one in your PC.

You think you have hardware RAID on your PC - I'm willing to bet you don't - not unless you're running a server grade system.  The reality is that the majority of desktop systems out there that offer RAID, only offer RAID0 & RAID1, and do so using the system processor - if there is no dedicated RAID processor and XOR then it's not hardware RAID - the writes are being handled by the disk controller drivers and the system processor is doing the slicing & dicing.  Post the make & model of your motherboard and I'll show you the details.

For what it's worth - I have not yet lost data upgrading my firmware - and all of my resyncs have worked and believe me - I have pretty much put my DNS-323 through the wringer when it comes to it's RAID capabilities.

One more thing - this NAS server, like many low cost NAS servers, runs embedded linux.  The firmware IS linux - the only reason for updating the firmware is to update the linux "distro" (I use that term loosely) so why should it be so strange that updating the firmware also updates the kernel?

Wizard wrote:

Does no-one take the time to research what they plan to do before they do it?
I cannot afford a RAID5 big box ...

What does RAID5 have to do with anything?  It's not an option on this box - and every piece of hardware I've seen offer RAID5 has also offered RAID0 & RAID1 as options.

You've already admitted making a bad choice - D-Link wasn't responsible for that choice, they give you the options, you made the choice - if you bought a box that offered RAID5, who's to say you wouldn't have made the same bad choice.  It's easy to do - every other option reduces your storage capacity.

Sorry, the RAID on my pc is not fully hardware, but there is a processor controlling it, the RAID controller and not the SATA controller.
It seems to me that the kernel doesn't need an update when the RAID sofware needs to be updated, except if the RAID is included in the linux kernel, am i wrong ?

About the firmware updgrades, lots of posts on this forum point the problem with the firmware upgrade process. You're lucky then.

The bad choice was to buy this box and not to choose a fully RAID0 system that seemed to work.

Word.

I told you : "He diligently posts the minutiae concerning RAID all over this forum." and I was right.

LOL  are those options mutually exclusive? do both!

fordem wrote:

This is not about this box.

I've said it before and I'll say it again - and again - and again - and as many times as I have to.

NEVER - EVER - store data you cannot afford to lose on a RAID0 array.

ALL RAID0 arrays operate in the same way - your data is sliced in separate "chunks" and written to the disks.

As you increase the number of disks in the array, you increase the probability of disk failure - with two disks, you double the probability of disk failure as compared to a single disk, with three disks, you triple the probability of disk failure, with four disks, you quadruple the probability of disk failure.

With a RAID0 array - failure of any ONE disk will cause the loss of ALL the stored data - with a four disk RAID0 array, you quadruple the probability of losing your data to a disk failure.

This holds true regardless of what you buy - I don't care if it's low end - Linksys, D-Link - mid range - Iomega, or high end - emc - the more disks you have in a RAID0 array, the greater the probability of losing the data to a disk failure.

I agree with you about the RAID0, you just forgot to mention : on a DNS-323 box.
However, the speed of the network interface is too slow for a RAID0 array (i reached 16 MB/s writing) and this was my mistake to think the gigabit interface was faster than that.

The RAID0 on my desktop works flawlessly (nForce 650i) at full speed (150 MB/s reading, 65 MB/s writing).

Wizard wrote:

However, the speed of the network interface is too slow for a RAID0 array (i reached 16 MB/s writing) and this was my mistake to think the gigabit interface was faster than that.

A gigabit Ethernet interface IS faster than "that" (gigabit Ethernet has a theoretical limit of 1000 Mbit/s [~125MB/s])
The reason for the slower performance of the DNS-323 probably has more to do with the 
limitations of the 500Mhz ARM processor, with only 64MB ram, performing the software raid.
more info: http://dns323.kood.org/forum/t738-Surve … Rates.html

Last edited by mig (2007-11-20 10:10:43)