How is a RAID drive seen?

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Stephen
Posts: 676
Joined: 01 Oct 14 9:15

How is a RAID drive seen?

Post by Stephen »

I'm considering buying am 8TB LaCie RAID as I cannot find a portable drive large enough for my growing image directory. I do not intend to use the RAID function however.

Would PSu see this RAID as 2 separate drives as that would defeat the object?

Thanks
Never say never change, but using Mac since 2005. Photo Supreme 3.3.0.2605. I endorse the interoperability of files between applications and systems.
snowman1
Posts: 394
Joined: 01 Jan 07 2:13

Re: How is a RAID drive seen?

Post by snowman1 »

RAID drives are seen as one drive. The "RAIDing" goes on under the hood (as they say in the US).
There are actually many different flavours of RAID some of which involve numerous disks. They offer various levels of protection.

Edit: apologies, just realised I had not read your question carefully enough. If you do not use the RAID function then it may depend on the specific brand as from a technical perspective I imagine the manufacturer could arrange it either way. I'd recommend checking the manufacturer's website for the specs if you haven't already.

But having said that I have a 2-disk RAID unit (a Buffalo Terastation). I have it configured to be in RAID mode - but I have just checked the manual and it looks like it presents as one disk if not in RAID mode. It has one network connection. Here is what my manual says - I've left in stuff that's not directly relevant in case it's also useful but bear in mind this is a Buffalo not a LaCie.

Edit 2: Now I'm not so sure, as further down in the manual I see it says: "Using JBOD: With JBOD, each hard drive in the TeraStation is addressed separately"
Also I should point out that mine is a NAS drive, but the same principles should apply.

>>>>> From the Manual:
Supports many types of RAID. The type of RAID arrays available for use depends on how many drives are installed in your TeraStation.
Notes:
• If you change the RAID mode, all data on the array is deleted. This is true for every procedure in this chapter. Always back up any important data before performing actions that affect your RAID array.
• Hard drive capacity is shown in Settings in actual gigabytes. The Properties window in Windows may show GiB instead, which will be a smaller number.
• After the RAID mode is changed (except when creating a RAID 0 array or JBOD), the TeraStation performs a RAID check that will take about 10 hours per TB. File transfers are slower during this period. While the I17 message is displayed in NAS Navigator2, do not turn off the TeraStation. If you do, the RAID check will start over.
• If the TeraStation is restarted or shut down while changing the RAID mode, the message displayed in NAS Navigator2 changes from I46 or I47 to I18.
• RAID 5, 6, and 10 are only available for models with 4 drives.
RAID 6
RAID 6 arrays are available for TeraStations with 4 or more hard drives. RAID 6 combines 4 or more drives into a single array. The usable space is equal to the sum of the capacity of all drives minus the capacity of two drives. For example, if 4 drives are combined into a RAID 6 array, the usable space is the sum of the capacity of 2 drives. If 2 drives in the array are damaged, you can recover data by replacing them. If 3 or more drives are damaged, your data is lost.
RAID 5
RAID 5 arrays are available for TeraStations with 3 or more hard drives. RAID 5 combines 3 or more drives into a single array. The usable space is equal to the sum of the capacity of the hard drives minus the capacity of one drive. For example, if 4 drives are combined into a RAID 5 array, the usable space is the sum of 3 drives. If one drive in the array is damaged, you can recover data by replacing the damaged drive. If two or more drives are damaged at the same time, your data is lost.
RAID 10
RAID 10 arrays are available for TeraStations with 4 or more hard drives. In this mode, mirrored pairs of drives in RAID 1 arrays are combined into a RAID 0 array. The usable space is equal to the capacity of the smallest drive multiplied by the number of hard drives divided by 2.
35
RAID 1
Combines 2 or more drives into a mirrored array. The available space in the array is the capacity of a single drive. Identical data is written to each drive. If a drive is damaged, data can be recovered by replacing the damaged drive. As long as one drive in the array remains undamaged, all data in the array can be recovered.
RAID 0
Combines 2 or more drives into a single array. The usable drive space is the total space of all drives used. This simple RAID mode offers faster performance than RAID modes that include parity. If a single drive in the array fails, then all data in the array is lost.
JBOD
This mode uses the hard drives inside the TeraStation as individual drives. The drive space you can use is the total capacity of all drives in the TeraStation. If any drive is damaged, then the data on that drive is lost.
<<<<<<<<

Apologies again for my original answer, I'm guessing you knew all about RAID!
Last edited by snowman1 on 15 Nov 21 19:15, edited 5 times in total.
G8DHE
Posts: 704
Joined: 21 Aug 17 12:58

Re: How is a RAID drive seen?

Post by G8DHE »

They are standard Seagate drives, if you disable the RAID function then you might as well have bought standard drives in the first place.
Geoff Mather (G8DHE)
Stephen
Posts: 676
Joined: 01 Oct 14 9:15

Re: How is a RAID drive seen?

Post by Stephen »

@snowman - Thanks, I must investigate

@GBDHE - Thanks, if you can point me to a small portable drive >6TB I would be most grateful. I have been unable to find one which is currently available for purchase.
Never say never change, but using Mac since 2005. Photo Supreme 3.3.0.2605. I endorse the interoperability of files between applications and systems.
G8DHE
Posts: 704
Joined: 21 Aug 17 12:58

Re: How is a RAID drive seen?

Post by G8DHE »

See here for drives starting at 6TB https://www.scan.co.uk/shop/computer-ha ... ard-drives

not sure what OS and filing system your using but NTFS does allow you to use Dynamic mode that allows multiple drives to be combined into a single letter.
Geoff Mather (G8DHE)
Stephen
Posts: 676
Joined: 01 Oct 14 9:15

Re: How is a RAID drive seen?

Post by Stephen »

Thanks, I could not get that link to work but I am in Mexico anyway. I have searched Amazon USA extensively and could not find a match. I did find an 8TB SSD which at $1000 is on the high side. But, there were several very negative comments from other professional image makers that I decided not to pursue that line of thought. I am using Mac.
Never say never change, but using Mac since 2005. Photo Supreme 3.3.0.2605. I endorse the interoperability of files between applications and systems.
Dismayed
Posts: 53
Joined: 22 Sep 09 20:42
Location: Boston, MA

Re: How is a RAID drive seen?

Post by Dismayed »

I use TrueNAS on a Xeon NAS that I built to store my photos. The pool consists of 4 drives, but PSU sees them as a single drive. I keep the PSU Postgres DB on a local SSD because the performance is much better than across the network, but I back it up to the NAS.
“There are three kinds of men. The ones that learn by readin’. The few who learn by observation.
The rest of them have to pee on the electric fence for themselves.”
~ Will Rogers
gcorbin
Posts: 110
Joined: 21 Aug 06 11:31
Location: Brisbane

Re: How is a RAID drive seen?

Post by gcorbin »

It is unclear to me what you are trying to achieve, but have you considered using multiple portable drives for your photo collection, not one huge portable drive. This is my current method.

I currently have my photo collection on three different drives. My photos are originally downloaded from the camera to my laptop internal drive where I cull/process them. When I have finished processing them, they are moved from the internal drive to an external portable drive. When that portable drive filled up, I added a second portable drive and migrated to that drive instead. Thus, I have ended up with my oldest processed images on the first portable drive and the newer images on the second portable drive plus the images being processed on the laptop drive. (I also have backup copies of images on powered desktop drives so I don’t lose photos should a drive fail.)

PhotoSupreme handles offline photos easily and allows me to search and view image previews of images on the portable drives when not mounted. I only plug-in the portable drives if I need to access the full size image to share or reprocess that image. Thus, PhotoSupreme works well irrespective of where your image is located so having all images on a single drive or even a mounted drive is not essential.
fbungarz
Posts: 1826
Joined: 08 Dec 06 4:03
Location: Arizona, USA

Re: How is a RAID drive seen?

Post by fbungarz »

One thing, no matter what you do is this: ALWAYS make sure you keep a backup !!!
Any drive, RAID or no RAID, small or large drive WILL fail. The larger the drive the more you will loose, if you have no backup.
And RAID drives are especially problematic, because not only the disk drives may fail, but also the RAID controller. And even if the drives are perfectly OK, when the controller fails the data becomes inaccessible (unless you use mirrored RAID, which simply means data are mirrored to two drives and thus this is a form of backup).
Once the controller fails it is often very difficult if not impossible to re-construct the RAID. So, if you invest in a RAID, best make sure you buy two with identical specifications and use software to always keep one as a backup (ideally you would need a minimum of two backups, one on-site, a second one off-site, alternating between the two).
Don't put all your eggs in one basket.
I am no fan of RAID. It seems like a dream: one gigantic drive, everything in one place. So easy to manage, right? But what when it fails?
JOBD (= just a bunch of disks) is a pain to manage/organize, but when a drive fails not everything is lost...

My advice: put the database on a fast, relatively small internal SDD, then buy yourself an external hard drive enclosure (or just a docking station) and a bunch of large, old-fashioned HDDs for the images, and make sure you have at least two copies of everything.
So - rather two times 3 x 2TB HDDs for your photos rather than one large 6TB drive with no backup...

One more thing:
SSDs are all the rage. They are faster and without any moving parts often considered more fail-safe. That latter advantage is somewhat dubious. SDDs can and will fail. The disks are rated by their average read/write cycles. It is important to understand that those are averages. Although is rare that a whole SDD fails before its estimated life-cycle ends, errors tend to build up and sectors of the drive with time will fail. To some extent the way the data is written to the SDD avoids these problems by simply using different, undamaged sectors. But the drives are not fail safe! Yes, SDDs are much better protected against mechanical damage. You drop your phone, it still works. You drop a laptop with a traditional drive while it was writing to its hard disk? Good luck...

What I want to say:
In the US a decent 8TB conventional hard disk on Amazon costs ca. $150. The same size SDD is ca. $800, which means you get five 8TB hard disks for the price of one SDD of the same size.
==>
Get a good docking station (ca. $200, with fast USB 3.2 or Thunderbolt) plus four 8TB hard drives (ca. $600). That is the same price as a single 8TB drive (things might cost a little more in Mexico).
Then use two 8TB drives in your docking station (= 16TB) and use Sync Back to mirror these two drives with the other two (in a docking station you can easily swap drives in and out and thus keep things in-sync; if you have an extra $200, buy a second docking station and you won't have to swap drives).
Now you have 16 TB for photos with at least one backup (one of each 8TB drive). Much better (in my opinion) that investing everything into a single SDD (or even a RAID).
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