2x2tb FW800 WD Studio Disk, zfs mirror 1 possible?

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2x2tb FW800 WD Studio Disk, zfs mirror 1 possible?

Post by mnos3c » Wed Dec 26, 2012 8:33 am

Hi everyone! I'm new to this forum and I'm zevo noob (I'm reading lot of docs about it).
After reading some Patrick Stein research and articles I'm becoming worried about hfs failure and want to switch to zfs for my backup drive.
I've got 2x 2Tb Western Digital Studio with Firewire 800 and many spare disks (1x1Tb, 1x750Gb, 1x640Gb, 1x500Gb, 1x320Gb, 2x250Gb).
Until now I put all my sensible data on 1 Studio and then sync with ccc with the other 2tb studio (a sort of manual-mirror 1 setup).
I would like to know if it's possible to use (and how) my studio disk (2x2Tb) with zfs and if it's possible to auto-sync them.
Then I would like to know if it's possible to create a pool with my spare disks (I really need suggestions).
Thanks in advance!


P.S: I'm using a mbp 2011 with lion
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Re: 2x2tb FW800 WD Studio Disk, zfs mirror 1 possible?

Post by GregB » Wed Dec 26, 2012 10:58 am

Hi - I am a noob too, but I will offer some suggestions anyway, and hope somebody corrects any errors.

To keep your data safe you generally want to have the data backed up several disks of course. Having a bunch of small discs can be messy depending on how many disk you can put in your computer. You don't say what kind of computer you have how the discs are attached but the general idea would be to have a zpool made up of these smaller discs another zpool made up of a larger 2 TB disks and maybe another 2 TB disk that you keep off-site.

Because you want to use up these smaller discs it would seem to make most sense to have them currently attached to your computer, or at least some of them and then use one of the big 2 TB disk to store offsite. That means the smaller discs would have to have at least 2 TB of storage and be in their own zpool. I would use the one terabyte, the 640 GB in the 500 GB disks and put them in one Z pool. Save some of those spare disks to boot from in the case your main system partition with Mac OS X dies. This is but one way to use your spare disks.

Some things to consider:

Create an other ZPool using both of your 2 TB disks. They can be mirrored. To remove one disc for off-site storage, I believe, you can mark it off-line and then detach it and store it somewhere off-site. You can still sync the 2 Zpools, and then occasionally fetch the off-site disk, attach it, then market online. The mirrored 2 TB storage Z Poole should re-sync.

Alternatively, use the off-site disk with the HFS file system.

Just some ideas for you to toss over.

OOPS- MBP. Above too messy. Mirror 2tb disks in one pool, use your other disks to backup important archival data and put offsite.
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Re: 2x2tb FW800 WD Studio Disk, zfs mirror 1 possible?

Post by mnos3c » Wed Dec 26, 2012 2:09 pm

Thanks for your reply. I spent last few hours trying to understand which is the best way to secure my data. I think that I will mirror the 2tb disks (but I will lose the encryption and I don't like it so much...).
My question is: if during the resilvering I noticed checksum error, I MUST replace disk or bad sector will be signed and I can continue to use the disk with bad sector "safely" (in mirror)?
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encrypting one disk, keeping an encrypted copy

Post by grahamperrin » Thu Dec 27, 2012 5:38 am

mnos3c wrote:… mirror the 2tb disks (but I will lose the encryption …


For encryption, you can combine two pool technologies: Core Storage and ZFS.

Give each of the two disks to Core Storage. Use Disk Utility to set a password at time of creation of a JHFS+ volume.

Then for each disk, give the JHFS+ part to ZEVO.

Use the first of the two ZFS pools to store whatever you like, aim to use no more than 1.6 of 2 TB (aim for twenty percent free).

Periodically send snapshots of data from the first to the second, so the second becomes a copy – not exactly a mirror, but as good as. There are open source scripts to simplify the send and receive routine.

----

What's above does not include remote backups, it's just to demonstrate that you can:

  • use Apple Core Storage to encrypt at one level, use ZFS at another level
  • have an encrypted copy.

For remote backups my first choice should be Backblaze, but it's on the shortlist of things that may be imperfect with ZEVO.
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Re: encrypting one disk, keeping an encrypted copy

Post by mnos3c » Thu Dec 27, 2012 6:40 am

grahamperrin wrote:
mnos3c wrote:… mirror the 2tb disks (but I will lose the encryption …


For encryption, you can combine two pool technologies: Core Storage and ZFS.

Give each of the two disks to Core Storage. Use Disk Utility to set a password at time of creation of a JHFS+ volume.

Then for each disk, give the JHFS+ part to ZEVO.

Use the first of the two ZFS pools to store whatever you like, aim to use no more than 1.6 of 2 TB (aim for twenty percent free).

Periodically send snapshots of data from the first to the second, so the second becomes a copy – not exactly a mirror, but as good as. There are open source scripts to simplify the send and receive routine.

----

What's above does not include remote backups, it's just to demonstrate that you can:

  • use Apple Core Storage to encrypt at one level, use ZFS at another level
  • have an encrypted copy.

For remote backups my first choice should be Backblaze, but it's on the shortlist of things that may be imperfect with ZEVO.



Thanks!
I have an idea for performance (core storage + zfs I think it will be slow).
I've got the first 2tb wd with chip aes encryption so I can easily format it as full zfs and use it when unlocked via wd smartware (so no cs layer).
The other disk for mirroring:
1st step: encrypt with cs
2nd step: format with zfs?
Or should I invert the steps?
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Core Storage with ZFS, link to an encryption topic

Post by grahamperrin » Thu Dec 27, 2012 7:29 am

mnos3c wrote:… core storage + zfs I think it will be slow …


Not in my experience.

I do run my MacBookPro5,2 in ways that can make it slow, but I don't count Core Storage as a factor.

… 1st step: encrypt with cs
2nd step: format with zfs?
Or should I invert the steps?


It's probably impossible to invert those two steps.

First, use Disk Utility to set a password at time of creation of a JHFS+ volume.

Then give the JHFS+ part to ZEVO.

For more details: in Ask Different, this answer to How can ZFS be used with encryption on OS X? – it appears long-winded, but after you've done it once it should make sense.

Also, in the ZEVO support forum:

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Re: Core Storage with ZFS, link to an encryption topic

Post by mnos3c » Thu Dec 27, 2012 1:03 pm

grahamperrin wrote:
mnos3c wrote:… core storage + zfs I think it will be slow …


Not in my experience.

I do run my MacBookPro5,2 in ways that can make it slow, but I don't count Core Storage as a factor.

… 1st step: encrypt with cs
2nd step: format with zfs?
Or should I invert the steps?


It's probably impossible to invert those two steps.

First, use Disk Utility to set a password at time of creation of a JHFS+ volume.

Then give the JHFS+ part to ZEVO.

For more details: in Ask Different, this answer to How can ZFS be used with encryption on OS X? – it appears long-winded, but after you've done it once it should make sense.

Also, in the ZEVO support forum:




Thanks for your reply. I read all the articles and I'm concerned about this sentence:

"So whilst the mixture of ZFS with JHFS+ on a single disk is possible, for most use cases the file system mixture is not recommended.

I can't understand in which situation is a really bad idea to use mixture and what is the real benefit to use mixture (not recommended) instead of simply use hfs+ in mirror 1 (when I manually sync the two external drive I can use sync2folder that enable checksum on single file so it's quite easy to me to understand if something goes wrong). I hope I was able to explain my point :oops:
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Link

Post by grahamperrin » Fri Dec 28, 2012 2:08 am

Anticipating questions, a few weeks ago I created a separate topic:

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