Media backup - Mirror or go cheap? Is mirroring mainly for bigger arrays?

Discussion in 'MacBook Pro' started by rawdawg, Jan 6, 2010.

  1. rawdawg macrumors 6502

    Jan 7, 2009
    At this point I wish I just got a MacPro instead, this wouldn't be a question..

    I have a new 17"uMBP, bought specifically to take advantage of eSATA through the expresscard slot. I do photography and video work. I bought the best possible card, the Sonnet Tempo dual eSATA, to offer highest transfer speed and because it's the newest technology.

    To accommodate my media I bought a OWC Mercury Elite Al-Pro 2TB RAID 0. It's great. I wish I got the Qx2 RAID 5 but it's a little pricey and expensive to upgrade, but at least it has redundancy.

    I need to have a reliable backup solution. Drobo is expandable but I've seen so many poor reviews. I could buy another Al-Pro 2TB RAID 0 and connect them both and do a software RAID 1 with them. Or I could buy a cheap 2TB eSATA external and do daily backups. I could also get a dock and fill up drives as needed...

    Is there really an advantage to mirroring other than if my drive fails in the middle of a job? Wouldn't the software RAID needlessly slow down my system?

    Even if I did get the Qx2 RAID 5 it is bad to rely on such a system by itself to both store and backup my media or is it in itself a very reliable solution?
  2. pprior macrumors 65816

    Aug 1, 2007
    You are confusing backup with redundant disks.

    If you merely hook up an external drive and raid-1, then you've got redundancy, but you don't have backup.

    I own a drobo, and a qx4. the drobo is slow (version 2) but you can get them cheap and not bad if you've got extra disks around to toss in for a time machine drive. the qx4 is much faster, but as you note you do NOT want to have backup and data on the same array.

    It sounds like a 2TB drive in an external enclosure with time machine set for that drive is the way to go.
  3. rawdawg thread starter macrumors 6502

    Jan 7, 2009
    pprior, thank you very much for taking the time to reply.

    I understand what you state about the difference between a backup and redundancy. But wouldn't the redundant disk in a RAID1 array serve as an adequate backup? Although I did feel unsafe using the Qx2 RAID 5 for redundancy and a backup for some reason - I think because I feel a backup needs to stand on its own. But wouldn't the redundant disk in a RAID 1 be on it's own? I would really appreciate your thoughts on this, maybe there's not something I fully understand.

    Do you like your Drobo? I've read so many poor reviews of them not working / crashing / not rebuilding itself like it should. Not to mention it's so slow ~50MB/s for the V2. You say it's useful as a time machine but would you trust it as a backup for important media files?-- I would probably set it up to time machine my whole system including those file.

    I would just get the 2TB external but I'm already using time machine for my 500Gb main system and I'm unaware of a way to do 2 time machines.

    What is the ideal backup solution of important files in your opinion? Perhaps I'm not understanding the proper ways to protect such files. Thanks!
  4. pprior macrumors 65816

    Aug 1, 2007

    The reason the redundant disk is not a backup is simple: what if you delete the file or your file system becomes corrupted - you now have two disks with the exact same corrupted files or missing files. Or someone edits something wrong - same thing.

    RAID1 will "backup" for a hardware failure, but that is just one reason backups are needed. User error, file system corruption, fire/flood/theft, etc are other reasons to back up files.

    My Drobo (version 2 firewire) routinely got 15mb/sec writes once it was more than 25% full. No way it ever got 50mb/sec. I still use it for backups , just not my main system backup as it was too slow for my use as I'm commonly backing up several gigabytes of new data. When I shoot a soccer tourney I might have 20-30GB in raw files, and that takes a long time at 15mb/sec.

    As to the time machine backup, you can backup as many source disks as you need, just one destination disk. So if you have a 2TB disk, you can backup your 500Gb + the extra you have.

    My backup strategy is fairly complicated. Here is what I do personally. Keep in mind my main backup needs are for photos. I have almost 1TB in digital assets at this point.

    1) When I import Raw files, Lightroom makes an immediate backup to another disk as they import
    2) Time machine makes backups of both of these disks (so now I have 4 copies, plus versions if I update/edit) to an external drive. I used to do this to a drobo and may eventually to back to a raid5 for my time machine but for now it's just a single external eSATA drive.
    3) Once a month (if I'm diligent) I backup my files to a hard disk via a quick dock that I rotate into a fireproof safe
    4) I keep an extra copy on the drobo, which is down in my basement equipment room
    5) I upload all files via mozy to remote backup site

    The thing I'm weakest on is #3 - I nearly always forget to do this or get too busy. In my experience, at least for me the more automated a backup system is, the more likely it will be done, which is part of why I love time machine.
  5. rawdawg thread starter macrumors 6502

    Jan 7, 2009
    Great reply pprior, I really appreciate you sharing your strategy.

    I said 50mb/s because that's what the Drobo people told me would be top speed with FW800. I fully believe you when you say you get much less.

    I too work with video and very large files. On an average day I make changes upwards of 100+Gb. Many times these renders are intermediate temp files as I work with them so I don't need time machine backing them up and taking up room. If I do this work on my 2TB Al-Pro RAID 0 I could get the external to only backup that array once a day. I then also have a 1TB external running time machine with my main 500Gb system and housing other temp files. I guess that would be a good solution for me.

    I do have another lingering unrelated question for anyone who may be reading. My RAID 0 is fast and I love it. A lot of time I do conversions of giant 50Gb video files on that drive. I've always wondered if I should be reading from the source drive and writing somewhere else. i.e. Is it bad for me to work on such a large file and rewriting all on the same disk? (edit -- I've created a new thread for this last question - )

    pprior, thanks again for your input.
  6. m85476585 macrumors 65816

    Feb 26, 2008
    Firewire 800 is capable of 70-75 MB/sec, although a specific device like a Drobo might be slower. Most large 1TB+ drives are capable of more than that by themselves, so RAID0 over FW800 might give you no benefit.

    Not all fireproof safes are good enough for hard drives. Most cheaper ones work by releasing a small amount water inside or something like that if they are in a fire. That keeps any paper from burning, but internal temperatures will be very high, possibly hot enough to damage a hard drive. More expensive "media safes" are typically designed to keep electronic media such as CDs, DVDs, and hard drives safe in a fire. If you rely on your data and you can't afford to lose it in a fire, a media safe would be a good investment. Alternatively, you could get a safe deposit box at your local bank and swap out hard drives there every few weeks.
  7. pprior macrumors 65816

    Aug 1, 2007
    Very good point about the safe - I neglected to specify that I store my hard drive in a specific media safe (it's pretty small, wish I had a full sized media safe) which is then put into a large fireproof gun safe.

    As to your other question, in general I always try to read and write to different drives when editing. I have a scratch disk (that time machine ignores) for temporary renders and is what photoshop uses, etc. This is on a mac pro however, so I have extra drive bays available (though I wish I had 4 more!). Some editing is processor intensive and so write speeds are not going to be the limiting factor. However HD video can demand significantly higher speeds.

    You could pull up activity monitor and watch what kind of processor use and disk drive use you are seeing - might get a clue there.

    Again, what I would do in your situation would be to get a 2TB drive and use it externally for time machine for your whole system. A raid1 version would be even better. Exclude your folders where the temporary files are placed so they don't use up all your space. Use the other smaller drive as scratch or other storage. That seems a nice solution for initial backup, then you just need to address longer / secure archiving for stuff that is really important.

Share This Page