File compressibility is not file system specific. The only advantage ZFS has is that 1) is has support for compression built-in, and 2) it has better file block allocation allowing small files to waste less space (compared to a file system that uses fixed allocation blocks).
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ZFS in Latest Leopard Builds
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File compressibility is not file system specific. The only advantage ZFS has is that 1) is has support for compression built-in, and 2) it has better file block allocation allowing small files to waste less space (compared to a file system that uses fixed allocation blocks).
Yup - That's what I meant...if it will be the default for all users or if it will just be an option for those that understand it and choose to utilize it.
You mean I shouldn't think of the first internal hard drive in the system as the C: drive? The next one as D:, etc... [Head explodes].
Drive letters in Windows annoy me to no end.
B
By the way, you couldn't store the Earth in a 2^128 bit hard drive. Maybe you could store a person, but only with some serious compression algorithms.
So, in conclusion, the Earth has more data in it than a ZFS HD can deal with.
Just thought you should know.
I'll save you from the wierd logic and very large numbers.
So, in conclusion, the Earth has more data in it than a ZFS HD can deal with.
Just thought you should know.
I'll save you from the wierd logic and very large numbers.
This whole pooling feature seems to be the thing that has people most excited about ZFS. What happens if I have two drives inside my computer - one faster one for large files and one slower one for everything else. Now i want to know and assign where each of my files go and this feature is useless to me.
Let me start by saying I know VERY LITTLE about ZFS
Also, does this (or can this) relate in any way to the new hard disks which have built in flash memory - to speed up the most common read requests? (eg at OS startup).
I have no idea what extent this goes to. I'd love to be able to "give away" all the free space on each Mac in a network, into a central network pool. And from that have a "virtual OSX file-server" drive for every machine. Build in redundancy would be required, of course, for when a machine dies or is turned off.
Or (... a little more reliably...) if I have a central network file-server, instead of using a RAID for redundancy, how about using the excess disk space on each workstation in the network?
Does ZFS allow that kind of concept?
Very good question. I certainly want files I access all the time on the faster partition. If it does that automatically that's great - I'm not sure whether manually putting it on a slower drive would make much difference????
Also, does this (or can this) relate in any way to the new hard disks which have built in flash memory - to speed up the most common read requests? (eg at OS startup).
That'd be very interesting (though I'm not in a position to use it anymore).
I have no idea what extent this goes to. I'd love to be able to "give away" all the free space on each Mac in a network, into a central network pool. And from that have a "virtual OSX file-server" drive for every machine. Build in redundancy would be required, of course, for when a machine dies or is turned off.
Or (... a little more reliably...) if I have a central network file-server, instead of using a RAID for redundancy, how about using the excess disk space on each workstation in the network?
Does ZFS allow that kind of concept?
Well based on one proof of the ability of matter to store data... a fully populated ZFS file system would require around 136 billion kilograms of matter... which is about 43,970,588,235,294 times smaller then the mass of the earth but of course far larger then the mass of a person.
This assumes perfectly efficient storage of information by that block of matter... which isn't feasibly possible... so you likely need several orders of magnitude more matter to store a fully populated ZFS file system.
ZFS can hold more
No ZFS can hold more data "if 1,000 files were created every second, it would take about 9,000 years to reach the limit" (source wikipedia)
No ZFS can hold more data "if 1,000 files were created every second, it would take about 9,000 years to reach the limit" (source wikipedia)
So if I have a 40 Gb HD, add a new 250 Gb HD to the pool that would bring my total HD space to 290 Gb. Now, if I have 20 free Gb in my 40 Gb HD, and 30 free Gb in my 250 Gb drive, can I copy a 40 Gb file without there being a problem? What if a file (a really big one) spans multiple hard drives and one drive is lost? is there a way to fix that? Obviously someone with the need for a file that big is pretty careful about backing up, but that's another story...
Mac os X can't boot from it
PEople do know that ZFS can't be used as root file system which means no boot capability for Mac os X right? but Apple does speed up things when they want it for them so hopefully they can get the ZFS Boot project team working an that
PEople do know that ZFS can't be used as root file system which means no boot capability for Mac os X right? but Apple does speed up things when they want it for them so hopefully they can get the ZFS Boot project team working an that
Some interesting blog posts by ZFS folks...
128-bit storage: are you high?
ZFS: The Last Word in Filesystems
RAID-Z
ZFS End-to-End Data Integrity
SEEK_HOLE and SEEK_DATA for sparse files
Smokin' Mirrors
You say zeta, I say zetta
ZFS Block Allocation
128-bit storage: are you high?
ZFS: The Last Word in Filesystems
RAID-Z
ZFS End-to-End Data Integrity
SEEK_HOLE and SEEK_DATA for sparse files
Smokin' Mirrors
You say zeta, I say zetta
ZFS Block Allocation
No that won't work. for two reasons
- The boot device can't be ZFS
- The operating system can't be stored on ZFS
But on to your question -- First off you don't need to have a large file to span disks. even a smaller file will span disks, parts of it will be distributed over the disks in the pool. So really ALL files are distributed over all the drives. This makes it fast as we can do reads in parallel.
What happens when a drive fails? Typically you get a notification and the failed drive is taken off line by the system. Reads can continue because data are stored redundantly. If you are lucky you have a hot spare installed and the system will spin up that drive and reconstruct the lost data on that drive in the background. If you don't have a hot spare, go buy one. You can configure various levels of redundancy so that you can survive one, two or more drive failures with out going down. In a large data centers they might keep a half dozen drives plugged in as spares, so they could loose tha many drives before needing to call the repair guy -- This is not new. We have a big array of disks downstairs. It is a 6 foot tall rack with about 80 drives. The technology is about 20 years old now.
What's new is that ZFS generalizes the concept so well and integrates it into the file system layer.
Going back to spanning drives -- if the file didn't span two or more drives then it would be lost if the drive it was on failed. right? So they are ALL spanned and written redundantly. even very small files
This is where Apple will need to add value over what Sun has given us. Apple will need to make a nice interface. Currently Apple allows you to build a RAID 5 system with a set of external FW drives. This is not such a great idea either.
I'dlke to see Apple ofer some better desktop storage options. They will need it if they want to sell those iTV things. Where to put 500 hours of video?
It would, but keep in mind for that to work you would have to have enough space on the remaining drives to accommodate all the data you are moving. So if I had two HD's and wanted to swap one out and add another, if both of those drives are full (which is probably why you are wanting to change HD's) you are going to have a problem. The solution would be to crack open the case, install your new drive as a third drive, then after adding it tell the file system you want to remove the one older drive so it can swap the data around.
So you would have to have a machine with at least one more internal bay than the number of drives you wish have in the machine. Except, I suppose you could use an external drive as a temporary holding place. So then you only have to crack the case open once to add the new drive and remove the old one. Hey, I wonder if it would be possible to use the new drive as the temporary drive. So you put the new drive in an external case, hook up, add to storage pool and migrate data off the old drive. Then shut down the machine and move the new drive from the external case to the internal bay after removing the old drive, and everything still matches up in the file system!
ZFS not for MacBook? You're kidding, right?
With the smaller capacities available for laptop drives, ZFS and it's ability to compress on the fly AND not to waste space with minimum cluster sizes is going to be HUGE for portable users. Not for MacBooks? Indeed, they will benefit greatly!
Leopard is looking to be a much bigger update than I anticipated. It's going to have a lot more things than Tiger had. Tiger seemed more like a "features" update, whereas Leopard is overhauling a whole bunch of stuff, while still giving us some cool features. Every major update has done that, except for Tiger to an extent. So, I guess you could compare Tiger that middle movie in the trilogy that doesn't do as much but is necessary to get you from one to three. **cough, cough** Pirates of the Caribbean **cough, cough**
Mmm. 640K ought to be enough for anybody, right?
Ohhh I so wanted to use that!!! As soon as I read that quote I was going to write that exact phrase.
The rest of that wiki is very interesting as well.
on demand boiled shrimp and lobster. Need I say more? Not to mention getting rid of those pesky whales and their incessant singing.
Yes, that certainly explains why Time Machine exists in the current developer's builds that are running on HFS+
ZFS would make a great basis for an implementation of Time Machine (read as: where we are going) but the program itself will not require a ZFS file system, it will be compatible with HFS+ for current users' sake.
I'm hoping for an HFS/HFS+ type transistion: ZFS will be in OS 10.5, you can choose to reformat your hard drive and start using ZFS for your boot partition, or keep using HFS+ for now. If you do change to ZFS you'll get better Time Machine performance, the pooled storage, ect.
Then at some point in the future (10.6, 10.7?) they will drop the HFS+ and you'll have to use a ZFS file system to upgrade.
Everyone keeps talking about how ZFS booting is not ready yet. Silly users, ZFS is Open-Source, is it not possible Apple has been working on booting ability on their own and have solved the issue for 10.5?
One thing that will be a problem in the beginning is there will be no DiskWarrior, ect to repair drives with. But given the features of ZFS, I wonder what use there would be for diagnostic programs to begin with.