[SOLVED] NAS or HDD enclosure for RAID 5

[ezra.luandre]

Hi all,

I have a need to build a storage that can handle RAID 5. I've read that if there's a failure in one of the drive RAID 5 can safe the data by changing the problematic drive. From what i understand after changing the drive, RAID will compiling all the data for the new drive and compiling could take a time depending of how big the drive is. And this is my question about RAID:

1. Does compiling the data take a lot of time, like if the storage is 10 TB does it take a whole day or even a week to compile it?
2. Is it safe to turn off the computer when the data is compiling? and this is the part where NAS and enclosure become preferable.

 

[Lutfij]

The time taken will depend on the data you're trying to have copied over to the new drive to reestablishing the RAID array. Now, the drives and the enclosures need power to operate.

 

[kanewolf]

Hi all,

I have a need to build a storage that can handle RAID 5. I've read that if there's a failure in one of the drive RAID 5 can safe the data by changing the problematic drive. From what i understand after changing the drive, RAID will compiling all the data for the new drive and compiling could take a time depending of how big the drive is. And this is my question about RAID:

1. Does compiling the data take a lot of time, like if the storage is 10 TB does it take a whole day or even a week to compile it?
2. Is it safe to turn off the computer when the data is compiling? and this is the part where NAS and enclosure become preferable.

RAID is not a replacement for backups. It only protects against a drive failure. There are lots of other ways to lose data. And data loss during the rebuild (your "compiling" phase) is also quite common.

Choosing a RAID type, depends on a how much total space is required, and what the usage pattern is. RAID5 requires data to be written to multiple drives AND information (parity) to be calculated and written to disk. RAID5 also requires more drives than other types. 3 or more drives are required.

 

[USAFRet]

Time for rebuilding a RAID 5 after replacement of a failed drive depends on how much data.
From my own experience in my QNAP NAS, approx 1TB = 1-2 hours.

And no, you cannot power it down during that process.

As above, RAID of any type is not a subsitiute for a true backup. That RAID only covers the physical loss of a drive. It does nothing for all the other, more common, forms of data loss.