kmod's blog

16Dec/093

Why mozy is terrible

Disclaimer: I am now an employee of Dropbox, and though I see Mozy and Dropbox as providing distinct services, some may see them as competitors.

I've started to think about backup again lately, since I have more and more files that would really suck to lose.  Until now I've used a combination of Dropbox and Jungledisk to store my files -- Dropbox for the small things that I always need with me (and nothing more, since I really dislike how you have to download everything onto every computer that you link to your account), and Jungledisk for redundancy (yes that's paranoid) and for backing up some other, bigger things.

But the problem is that both of these services have $/gb costs.  And lately I've become a huge fan of VMs -- for every big project that I have that requires lots of setup (for instance lots of custom programs for a custom development environment) that is hard to redo, I simply create a VM with it all set up.  Then when I need to work on my laptop, just transfer it over and I'm ready to go!  Or when my desktop breaks down and I need to reinstall the OS, just reinstall VMWare and load up the VM and I haven't lost anything!

But the problem is that these VM images are huge.  I suppose if I had a lot of time there are things that I could do to bring that down, but the point is that they're on the order of 10gb each.  And I don't need them so badly that I want to pay $2/month for each of them.  So I decided to look into unlimited backup options.

I looked at Mozy and Carbonite, since they both advertise themselves as being unlimited.  I did some googling about them, and Carbonite has a bad reputation of closing off people's accounts when they use too much space.  WTF.  How are they claiming to even offer unlimited backup?  Well, those reviews were from a while ago, and some support people have responded to them saying it's not the case anymore.  But they still have in their TOS that they're going to close down your account if you use too much space.

So I sent Carbonite an email asking them how much "too much space" is, when they'd shut down my account.  Because the worst part is not knowing.  I got back an email from a clueless support guy that was obviously just copied and pasted but didn't have anything to do with my question.  So I decided not to go with Carbonite.  (Though someone else did get back to me saying that they don't really terminate your account.  They just throttle you after 200GB.  Great.)

So instead I went ahead and set up Mozy.  I've used their free version in the past and been fairly happy with it (though I noticed some performance problems), so I decided to sign up for their unlimited backup plan.  They didn't have any bad reviews in the past, so I signed up for one month and set up an initial backup of 350GB.  And then the problems started.

First, it seemed like they were throttling my account.  My MIT internet has a great 1mbps 1MBps upload speed, so I thought I'd be able to upload 3gb an hour.  Instead, what would happen is that the client would upload exactly 100mb, then stop and say "Communicating with servers..." for the rest of the hour.  I figured that they were throttling upload speeds to 100mb an hour, since that's probably what most people can get, so I emailed them saying that they didn't mention that there'd be throttling and I was unhappy.  They asked me to give them log files and stuff (which I checked and were empty), but then the next day the problem went away.  So I figure they just unthrottle anyone who actually cares.  Oh well, I'm now backing up at 7mbit/s, so I'm happy.

But then the backup crashes.  And again.  and again and again and again and indefinitely.  Why?  Because Mozy encrypts the entire file before sending it over the link.  This doesn't sound like a terrible idea for small files, which most files are, but for 10gb vm images, it sucks.  Especially since Mozy puts the encrypted files in your windows temp folder.  I know how to move the temp folder, but I have it on my SSD so that it's fast, but that also means that I don't have 10gb of temp space.  So it would try to encrypt the 10gb file, fail because there's not enough space, and cancel the entire backup.  Great.  If I want to use mozy I have to move my temp file to one of my larger drives.  Well, it's not the end of the world, so ok I'll go ahead and do that.

And then now Mozy has gone completely beserk, and has killed my computer. It was doing 40k iops WRITES on my drive.  Ok I guess it can achieve that because they're small sequential writes, but still wtf, it means that I can't do anything else with the drive.  And then another stupid piece of their code came into play: they do ALL OF THE ENCRYPTION at once when doing the backup.  Usually they're smart and only encrypt a few 100mb in advance, but somehow the program has decided to encrypt the rest of the 160GB of my backup.  And there's only 140gb of space on the machine.  And then it used it all.  But it didn't die this time -- I guess it knew that it didn't need all of that space.  So instead it just spun.  I have no idea what it was doing.  But it hogged the entire drive until I was able to get rid of 20gb of stuff from that drive to another.  And do you know how long it takes to do that when there's a program trying to do 40k iops on the drive?  A long frickin time, that's how long.  They even taunt you with this nice little "throttling" slider that you can use to throttle the backup process.  I moved it, and guess what, it did nothing.  Still 40k iops.  I have no idea what happened, but eventually I was able to get rid of enough stuff and then the encryption could continue.

So the result is that Mozy is one of the most demanding programs that I've ever seen.  And it's been 2 weeks and I've only uploaded 200gb, when I should be able to upload 75gb a day.  So yeah it's kind of unclear if I'm going to keep on paying them for the service.  Eventually I'm going to have a personal dedicated server somewhere that I can use for stuff like this.  Until then, I'm either going to have to deal with the crap that is Mozy, or suck it up and pay the $.15/gb/month for Jungledisk.  Or not back the stuff up and hope nothing goes wrong.

Update: I've finally managed to upload all of my data to Mozy, and now it seems pretty good -- it does nice small delta syncs even when I touch large VM images.  And the throttling for the most part works.  It's just very frustrating to do a large initial sync -- which I suppose Mozy has no incentive to change.

Comments (3) Trackbacks (0)
  1. For someone from MIT, you realize that your math is somewhat f*cked right? mbps is megaBITSpersecond – all your calculations indicate that you are under the impression that it is megabytespersecond.

  2. You’re right — I got sloppy with my terminology (I write “mb” for megabyte and “mbit” for megabit, which causes problems when I then want to talk about rates). Technically, I should also be writing MiBps and GiB instead of the SI variants. Sorry for the confusion; I’ve updated the post.

  3. Good article, you sound like a good candidate for backazon.com. Secure Amazon S3 and live tech support, can’t beat it, i love it.

    Cheers
    Eric


Leave a comment

No trackbacks yet.