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The Graveyard - Products No Longer Supported => D-Link Storage => DNS-323 => Topic started by: dmnc on October 05, 2009, 06:31:08 PM
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I have 2 x Seagate 1.5Tb drives in RAID1, and to access these from Snow Leopard I will need to upgrade the firmware of my DNS.
What is the safest way to do this without risking to lose all my data? Can I remove one of the disks, upgrading with only half the RAID in the NAS and, assuming everything goes well, put the other disk back? If I do this, will the RAID still be sync'd or will it have to reformat/resync the second drive when I put it back in?
If I keep both disks in the NAS, it might want to format or whatever after upgrading, and even if not something might still break. Keeping one disk outside during the upgrade would at least allow me to mount it in a computer should anything happen. And if so, does it matter if I take out the left or right disk?
These might be noobish questions, but I do want to be on the safe side, rather than lose all the stuff I've collected over the years.
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There's only one safe way - and that is after a backup.
Consider this - even if you don't upgrade, "something might still break" and your data could be gone.
And RAID1 is not about backup.
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Yes, but technically, once I take out one of the disks, doesn't this cease to be RAID (and therefore redundancy) and its suddenly just two drives backing each other up?
If there are risks involved with the procedure I described, what are these? For backing this stuff up otherwise, I'd have to buy a second NAS and clone everything to there. And then I'd have 4 disks with identical content, surely this sounds like overkill?
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What firmware are you running and what firmware do you want to upgrade to?
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Yes, but technically, once I take out one of the disks, doesn't this cease to be RAID (and therefore redundancy) and its suddenly just two drives backing each other up?
Technically, you are correct, taking one disk out will provide you with a backup for the firmware upgrade.
However, when you reinstall the removed "backup" disk into the DNS-323 to recreate the RAID, you
will be doing this procedure without any backup. If anything goes wrong, you could lose data.
The only way to "be on the safe side" is to backup your data. Where you backup your data is
your choice, floppies :D, tape, CDs, DVDs, BlueRay DVDs, a USB hard drive, another NAS?
I agree making a backup to a RAID1 NAS seem like overkill to me, too. (I would use a USB hard drive.)
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Yes, but technically, once I take out one of the disks, doesn't this cease to be RAID (and therefore redundancy) and its suddenly just two drives backing each other up?
No - technically - once you remove one of the disks, what you have is a degraded RAID array, with no redundancy, and no backup - should I say it again for good measure - RAID is not a backup..
If there are risks involved with the procedure I described, what are these? For backing this stuff up otherwise, I'd have to buy a second NAS and clone everything to there. And then I'd have 4 disks with identical content, surely this sounds like overkill?
The risks with the procedure you described are essentially the same as you would have if you were installing a new drive or replacing a failed drive in a degraded RAID array - and - given the history of the DNS-323, you are at a statistically greater risk of data loss than flashing the firmware with both drives in place.
On the subject of backup - as I've said before RAID1 is not a backup, so if all you have is the data on the two disks in the DNS-323, then you have no backup and if your DNS-323 were to fail taking your disks with it, you'd probably be in major grief.
I know - you're probably going to tell me that that is the reason you're asking the questions you're asking - but you're overlooking the fact, and I have pointed it out in an earlier post, that the DNS-323 can fail, even if you're not upgrading the firmware.
As for overkill - it's your data, it's your loss - I like to suggest to folks like yourself, that you weigh the cost of the additional hardware against the heartache and time you're going to spend recovering or recreating the data you lose, if it's at all possible.
Let's say you have a few thousand MP3s, and you have all the original CDs, and you can go rip them again - how long does it take, and how much do you value your time? Now - let's make that a few thousand digital pictures, memories of the last decade or so - can you replace those if they were lost?
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Let's say you have a few thousand MP3s, and you have all the original CDs, and you can go rip them again - how long does it take, and how much do you value your time? Now - let's make that a few thousand digital pictures, memories of the last decade or so - can you replace those if they were lost?
Let's just say I have a few thousand CDs. And ripping those again isn't an option.
And to answer the question from the high level member; what i have is 1.06 and what I'm planning on getting is the new firmware when it's out of beta that lets me use this NAS with Snow Leopard without changing all the passwords to numbers only.
Oh, and fordem: Why would I need to recreate the RAID when I put in the disk I took out? They'd still have both the same contents, it shouldn't have to do nothing to the disk but accept it as its long lost brother, right? Otherwise, my spider sense is detecting suboptimal implementation xD
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- Take one disk out of the DNS-323
- Power up the DNS-323.
- After it starts, turn if off again.
- Put the disk back in.
- Power up the DNS-323 again.
- It will insist in rebuilding the RAID-1 array, manual or automatic.
That's the way it works, you'll just have to live with it.
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Thanks for that crystal-clear answer. Unfortunately it wasn't the answer I'd hoped for. I've ordered a third 1.5Tb drive to back everything up to now, once it arrives I'll update the firmware on my DNS.
When going 1.06->1.08, should it require reformatting though? Or will the backup (if everything works like it should) be unnecessary?
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"if everything goes as it should", the data will be intact.
Of course, I wouldn't do this without backup...
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Per my understanding, upgrading the firmware from 1.06 to 1.08 will not do the HDD formatting. ;)
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Thanks everyone for your replies... I'll wait for the new HDD to arrive before I do anything. But if rebuilding a RAID is really so shaky with the DNS-323, is there any point to use RAID1 at all in it? Wouldn't I be better off having twice the amount of storage, then? Of course that'd require me to buy one more disk to have a complete backup, but if I can't rely on the RAID for anything, I'd rather not waste the disk space on it.
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Per my understanding, upgrading the firmware from 1.06 to 1.08 will not do the HDD formatting. ;)
By very careful how you make that statement - based on my tests, a disk formatted under 1.06 is accessible using 1.08 and an upgrade will not automatically cause or require a reformat - however - the disk formats were changed between 1.07 & 1.08.
I can't tell you what the difference is, but I do know that a disk formatted with 1.07 can be accessed using Windows XP & the EXT2IFS drivers, and a disk formatted in the ext2 file system under 1.08 cannot.
Without a more thorough understanding of the change I am not willing to state that a format will not be required.
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Oh, and fordem: Why would I need to recreate the RAID when I put in the disk I took out? They'd still have both the same contents, it shouldn't have to do nothing to the disk but accept it as its long lost brother, right? Otherwise, my spider sense is detecting suboptimal implementation xD
gunrunnerjohn has already answered this, I just want to add one thing - ALL RAID arrays work this way, lose a disk - flag the array as degraded, add a disk to a degraded array - do a rebuild - the only way around this is to not power up the unit with a disk removed.
Interestingly enough, you should be able to remove both disks, power the unit up, upgrade the firmware power the unit down, replace the disks (in the same slots please) and on power up it should recognize them as a valid RAID1 array. The ability to do a firmware flash without disks was added in 1.03.
Please note that should, I haven't tested this, but I do know that you can put a RAID1 pair in a new enclosure and it will recognize them with no difficulty.
Thanks everyone for your replies... I'll wait for the new HDD to arrive before I do anything. But if rebuilding a RAID is really so shaky with the DNS-323, is there any point to use RAID1 at all in it? Wouldn't I be better off having twice the amount of storage, then? Of course that'd require me to buy one more disk to have a complete backup, but if I can't rely on the RAID for anything, I'd rather not waste the disk space on it.
I need to make one thing VERY clear, although seeing as I have already stated it and you apparently still haven't gotten it - RAID is not a backup.
What RAID is about is continuing to have your data available even if a disk were to fail - a RAID array is not required to provide a mechanism to rebuild, even though that is a very desirable feature and although most manufacturers do provide it - there are some that don't.
Consider these scenarios ...
#1 - you are running a small business and your point of sale system does not have redundant disks, but you do backup to tape every night. At 9:00 am just as you're opening up you have a disk failure, so you call a tech who comes in and replaces the disk and restores the backup, but it techs the tech an hour to get there, and the process takes another hour, so you're without your PoS (and losing business) for two hours.
#2 - you are running a small business and your point of sale system has redundant disks which do not rebuild. At 9:00 am just as you're opening up you have a disk failure, but the system continues to function because the data remains accessible. You call a tech who comes in at 5:00 pm, backs up the system, replaces the disk and restores the backup - in this case you had the use of the PoS all day and lost no business.
That is what RAID is about - minimizing the impact of downtime - in this case by deferring the required downtime to a convenient period outside of business hours - it's not about backup, and so, if you don't need your data to be constantly available then you don't need RAID and if you can make better use of the disk space then by all means do so.
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I need to make one thing VERY clear, although seeing as I have already stated it and you apparently still haven't gotten it - RAID is not a backup.
Oh, thank you kind sir for lecturing poor stupid me.
And to everyone else, thanks for being helpful without being arrogant.
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Thanks everyone for your replies... I'll wait for the new HDD to arrive before I do anything. But if rebuilding a RAID is really so shaky with the DNS-323, is there any point to use RAID1 at all in it? Wouldn't I be better off having twice the amount of storage, then? Of course that'd require me to buy one more disk to have a complete backup, but if I can't rely on the RAID for anything, I'd rather not waste the disk space on it.
One of the least mentioned benefits of a RAID1 system is the ability to make a backup of all
your data right before you attempt to recover from a disk failure.
If a disk fails (in RAID1) the data remains accessible. Most people see this as an advantage to
minimize downtime for any activities which rely on the data. However, since the data is still
accessible at the time of repair, you can take a 'up to the minute of repair' backup of your
data, right before you attempt to recover from the disk failure. This 'up to the minute of repair'
backup will capture any data that has changed since your last 'regular scheduled' backup (say,
once a night at 2:00am). This 'up to the minute of repair' backup will guarantee you have ALL
your data saved, in the event that something goes wrong with the RAID1 repair.
If a disk fails, in a non RAID1 system, there is no access to the data after failure and you WILL
lose any data that changed between the time the last 'regular scheduled' backup occurred and
the time the drive failure occurred.
The reason I choose to spend the extra money to run a RAID1 system, is not because RAID1 is my
backup, (I run nightly scheduled backups), and it is not because I can't tolerate any downtime. I
use RAID1 to guarantee that ALL my data will be backuped and safe, before I attempt to repair
my RAID1 from a disk failure.
For me, that IS the point of RAID1.