Drobo

Before having drobo PRO

gents… good day

I am planning to have drobo pro and attached it to my mac mini server to use it as a share storage over my home network , before i buy it i have a couple of questions…

1- i will stick 8 drives with 2TB in the drobo pro with total 16TB capacity, when i reach 16TB of storage i will stick another 8 drives as a new storage capacity, suppose i need to use the old drives how can i use them over the drobo again !!!
As i know that once you put a drive drobo will automatically format it … do I misunderstand something or this is what really happened in such case ??

2- dual disk redundancy is used for data protection, it’s also used to reach the files faster, as i know it copy the file three times for protection purpose hence when you try to read a file you will read it from the three copies which will give you a faster read process since it reads from three copies instead of one copy, is it correct ??

thats it for now :slight_smile:

thank you in advance and please accept my apology if my English is not good enough as i not an English speaker…

Regards’

Hi

  1. i dont really understand the question

the drives you put into drobo are a PACK - they must be kept together at all times - your data is spread across ALL of them - you cant just pull out one 2tb and put into another 2tb to increase capacity. that si why drobo wipes drives when you put them in

if you fill up your 16tb - you will have to start slowly replacing the drives with 3tb drives

please read up on how RAID works - drobo is VERY similar. (wikipedia is good for this)

  1. no, that is not correct at all.

it stores one copy of your files - spread across all the disks - and also just enough data so that if part of your file is damaged - it can replace the damaged part

if could not store 3 copies of your files - or else you would only be able to put 5.3Tb onto your 16Tb array!

read how RAID 6 works - drobo with dual disk is VERY similar to that.

I am NOT trying to be nasty - but it is very obvious that you do not understand how drobo works - so please do a lot of reading on RAID and then come back and ask any questions.

i am not being unpleasant - i am just worried that you will lose data by accident if you do not understand how the drobo and other arrays like it work.

Chris

“” if you fill up your 16tb - you will have to start slowly replacing the drives with 3tb drives “”

once i replaced the drives from 2TB to 3TB for all bays i will have 8TB extra capacity and my old 16TB is just as it is, right ??

what about the old 2TB disks ?? dose it have data on it ? and i can refer to it any time if i want ?

thank you for advise, i believe you are extremely correct i am not familiar with RAID so i need to start reading a lot of RAID…

sorry for any disturbance

thank you

If you replace all your 2 tb disk with 3tb disk then you would be able to store 24tb of data (less what is used for protection)

And your 16tb of data will be safe

The 2tb disk will have data on them only drinks can read - you cab wipe them and use them in other computers no problems

thank you so much Chris, the point have been so cleared now

thanks again

I still like ACNC/JetStor’s RAID tutorial. It may be a little too technical until you’re more familliar with the basics of RAID though.
Single-disk redundancy on Drobo is very similar to RAID 5
Dual-disk redundancy on Drobo is very similar to RAID 6

Important things to understand:

  1. RAID does not necessarily make disk access faster. Except in the case of RAID 0, 0+1, and 10, it actually causes extra work.
  2. RAID does not necessarily mean your data is protected from hardware errors. RAID 0 in particular, has no protection whatsoever, and if one drive in the array has a failure, all your data is lost.
  3. No fault-tolerant storage, Drobo or otherwise, is a substitute for regular backups of your data to multiple, separate storage devices.

thank you for the added value i appreciated…

There are a couple of extra points. Firstly, I have found that dual disk redundancy is significantly slower than single not faster. In fact twice I have got so fed up with slow transfer rates that in the middle of a file write to the DroboPro FS I have turned off dual disk redundancy and watched the transfer rate leap up.

When you fill up your 2TB drives on the Drobo you can power down the unit, take all 8 discs out and put 8 3TB drives back in. You can then copy the data back to the DroboPro. If you keep your original 8 2TB drives together, untouched and safe, if necessary in the future you could re-mount them. This is the risky bit. You would power down the DroboPro, take the 8 3TB drives out; put the original 8 2TB drives back in and power up the unit. It should recognise your drives and it will be back in the state you left it. When you have finished with the old data you would power down and replace the 3TB drives back in. Personally I would not want to rely on this. I would fear that the DroboPro would not recognise the old pack and reformat the drives. Maybe I am just too cautious.

I think that my DroboPro is the best unit that Drobo have made, it is fast over iSCSI and very good value for money. This experience is on Windows, however.

Ian

of course dual disk redundancy is slower - its having to calculate twice the parity (and the second lot of parity tends to be much more computationally intensive.)

DRI’s official line is that it should be about a 10% penalty

“When you have finished with the old data you would power down and replace the 3TB drives back in. Personally I would not want to rely on this. I would fear that the DroboPro would not recognise the old pack and reformat the drives. Maybe I am just too cautious.”

it does this EVERY TIME you turn it on or off

it doesnt store information about the pack - it read it from the pack each time

doesnt matter which disk pack you put in there - it will read the information from it at boot time