FreeNAS project

In my previous post, I explained the benefits of ZFS.

I will the next weeks explain about my new project a home ZFS server. It will probably be based on FreeNAS, but I might switch to ZFSGuru.

The Hardware:

Asus E35M1-l Deluxe, a nice low power, economic AMD motherboard with 6 SATA ports and unofficial support for 16 Gb.

16 Gb Kingston Value RAM (2 x 8) tested and it is working

3 x 2 Tb Seagate 7200.14

1 SSD 60 Gb OCZ Vertex (leftover and nice for L2ARC)

Antec One Case

Antec VP350P PSU enough to provide all the hardware of sufficient power.

Currently, I am waiting for the case. It was not in stock and will arrive 2nd week of Januari 2013.

So to be continued…

L2ARC

In my previous posts are links posted about the advantage of ZFS.

I will repeat in short some highlights:

-Checksums watch over data integrety on disks.

-It can repair corrupt and bad sectors. ZFS has a repair tool called “scrub” which examines and repairs Silent Corruption and other problems.

-It makes silent errors (normally repaired by the internal software of modern HD) visible

-ZFS can function as a software RAID. However, it needs to have direct contact with the discs. A hardware RAID needs to configured as JBOD (Just a bunch of discs).

One of the most interesting features, I like, is: L2ARC

Most data will be cached into RAM memory, so it will be quickly available when needed.

If you add a SSD in ZFS, you can configure it as a second cache.

The read SSD cache is called L2ARC and is similar to Level 2 CPU cache.

The write SSD cache is called the Log Device, and it is used by the ZIL (ZFS Intent Log). Read more about this on http://en.wikipedia.org/wiki/Zfs. With ZIL ZFS can watch the consistency of its filesystem and its applications. This is a log almost never read unless there is a problem like power-loss. You can put ZIL on a different SSD.  However lots of read and write cycles in this log will happen and your SSD will break down quicker.

So the last one is not really interesting (you might want to mirror ZIL on a second SSD) for a home user like me. But L2ARC is. The read performance improvement is huge with a SSD as L2ARC read cache. Image this with a RAID and you will have a fast and reliable fileserver. It funcions a bit like Intels SRT technology, Seagates HDD with a SSD cache and  recently Apples Fusions discs (which is also a HDD plus SSD).

L2ARC is also safer then e.g. Intels SRT, because Intels system cannot detect when data on a SSD cache gets corrupt. ZFS can detect corruption on a SSD cache: it will simply deactivate the SSD as read cache and read the data directly from its normal filesystem.

So here you are. ZFS RAID with L2ARC for a safe and reliable fileserver.

I will soon tell more about the filesystem. It wil be my next project: a reliable AMD Brazos home fileserver.

ZFS part 2

ZFS part 2:

As mentioned in my previous post, I tested FreeNAS 8 under virtualbox. FreeNAS 8 is based on a minimal version of BSD with ZFS (or UFS if your resources are not powerful enough) as a filesystem. Configuration is done with a simple web interface.
It runs very stable, but you have to make sure to meet  the hardware requirements of ZFS.
As a rule of thumb you need for each TB storage 2 GB RAM. With deduplication (later more about this)  it becomes even more. For a 6 TB storage, it is useful to have at least 8 GB RAM, 12 and 16 are even better. Lately I see even posts of 20 GB RAM being necesarry.

Why would I put so much effort for a home NAS? There are easier solutions from Synology, for example? Which has gadgets like an itunes server, bittorrent client, etc?

First, gadgets that do not belong in a server. and if you really want: in FreeNAS, they are put into a jail as a plugin.
Secondly, like I have told in a previous post: our hard drives are getting bigger: 2,3,4 TB and 5TB has been announced for 2013. Here platters of 1 TB used. This means that there is so much capacity on a hard disk and data is put very close together. There is a chance that when data is going to be corrupt, you’re not going to know it  until it is too late and all your data from your disk is being lost. With ZFS you will notice this on time, before data is lost…

YOU MUST BACKUP THEN, KELLY! That’s true, are we doing this all the time at home? Of course, if you had to write a thesis of your studies you would have 50 USB drives and clouds to backup. But are you doing the same with your purchased videos, your home-made videos of your baby? Let just say that you have forgotten . And those extra usb drives you have just ordered,.came one day late. Years later, you still will  regret it.

ZFS has very good RAID capabilities that go beyond RAID0/1/5/6.
You can combine speed with stability. In short, very interesting possibilities for the serious home user, small office user or system/network operator.

Coming soon: RAIDZ

ZFS

For the problem of High Capacity disks in RAID there is now a better solution: ZFS

What is ZFS?

ZFS or Zettabyte File System is a new kind of filesystem. ZFS differs greatly from other filesystems, because the next generation filesystem also has the same kind of funcions that LVM and RAID can provide. We therefore call  it a hybrid filesystem. Traditional file systems are FAT32, NTFS, Ext3 / 4 (the latter is even more unreliable than NTFS)

Almost all existing file systems work on a storage device such as a hard disk. They are not made to communicate with multiple hard disks. A separate RAID layer is needed then for multiple drives and then placed on a filesystem. The file system is not aware of the fact that its data is placed on multiple disks is those two worlds are strictly separated.

ZFS works quite differently, it speaks directly to multiple disks and integrates the functionality of RAID, LVM and file system in one package. This has many advantages, especially in terms of reliability, but also performance.

Read more about the many benefits of ZFS (dutch):

http://gathering.tweakers.net/forum/list_messages/1452380. Cipher has very clear (for noobs) set done the benefits of ZFS

or

http://en.wikipedia.org/wiki/ZFS

There are really only 2 competitors: Btrfs (Linux) and refs (Microsoft). These are in a different stage of development as ZFS. ZFS is the most stable, (And Mr. Reiser is in prison …)

ZFS has been developed 10 years ago in the laboratory of IBM. Apple was once very interested and at the time (in Snow Leopard if I’m not mistaken) it was even hidden in the OS. Sun came to power and for political reasons, Apple removed ZFS. Apple continued to HFS +. (so sorry,  Apple). Everbody hopes now that with Oracle as the new owner of ZFS Apple will reconsider its former choice.

Where can you find ZFS?

In (Open) Solaris Oracle course. There are several paid and opensource versions: Nexenta, Napp-it, Openindiana, EON-zfs storage, etc.

But also in FreeBSD: mfsBSD, Freenas, NAS4FREE. ZFSguru.

Integration with Linux is not yet stable. And Microsoft has its own file systems.

Do you like to do things yourself (eventually appear unix commands of Linux, BSD and Apple together) then you can use FreeBSD ZFSGuru a server build. It has a complete FreeBSD build as a base. With ZFSGuru to control the ZFS filesystem.
IF you are a noob like me, you might like FreeNAS 8 (now owned by Ix systems) or NAS4FREE.
All this is open source and therefore free to download.

I myself tested FreeNAS 8 under Virtualbox and it runs very well and stable as fileserver. It has NFS, Samba, Apple shares, (s) FTP, iSCSI…, it’s all in there. FreeNAS is also based on a minimal version of BSD.