# UFS or ZFS with 4 sata disk



## BarbeRousse (Jan 10, 2011)

Hello,

   I' am upgrading a file server and want advice about file system choice for important data.
Before I used debian with a 3ware 9650SE-4LPML with four 750Go disks and XFS file system.

   3ware card and disks were replaced by four 2To new hard drive. The raid card will be dropped out.

   Now FreeBSD 8.1 amd64 is running.

Operating system is installed on a separated disk, 80Go IDE. System ram is 1Go and processor is a 1,6Ghz intel celeron socket 775.

   First, I would use geom with raid5 and UFS2 system file with acl enabled. But this raid mode isn' t available and it would be impacted by the famous "write hole".

   So, next is about ZFS with raidz engine.
   It is well designed for keeping data integrity on hard disk with redundant but, as other file system it is not protected against memory errors.
Since it use, I suppose, much more memory than other file system it would be dangerous to have full trust; silent corruption could appear.
   Tell me if I have wrong, it seems that using ECC memory may help but it require buying expensive hardware (intel Xeon with right chipset).

   Does raid5 with geom will be implemented in the official system development ? If yes, using UFS2 with disabled write cache and having UPS could be considered "safe" ?

   Or the best solution is to get ECC memory ?

Thank you.
Bests regards,


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## SirDice (Jan 10, 2011)

The amount of memory the machine has is rather low for ZFS. ZFS really likes to use a lot of memory and you'll need at least 2GB. It might work with less but it'll require some tweaking.


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## phoenix (Jan 11, 2011)

A few options:

Keep the 3Ware card, configure the 2 TB disks in RAID10, with UFS on top
Keep the 3Ware card, configure each 2 TB disk as a "Single Disk" array, which exposes them as separate disks to the OS; use ZFS to create 2 mirror vdevs in a single pool (RAID10 basically)
Ditch the 3Ware card, connect the disks to the mobo SATA ports, use ZFS to create a pool with 2 mirror vdevs (basically RAID10)

For options 2 and 3 above, you will want to stick as much RAM into the machine as you possibly can.  Aim for at least 4 GB.

Using the 3Ware card may lead to better performance, and will give you better management tools, but may be overkill.  Depends on what you want to do with the server.

This is the setup we currently have, using 9550SXU and 9650SE 12-port cards.  Our next storage server will be using LSI/SuperMicro/Intel SATA controllers (non-RAID).


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## BarbeRousse (Jan 11, 2011)

Hello,

   Thank you for your reply.

   I will chose option 3 but with raidz. I don't need performance just "reliability" ans lot of space.
This server is used as a file sharing with samba for two person every day and more, nearly 10, some days per years.
Some folder are personal other are for hosting project.

   Memory will be upgraded to 2GB and 4GB later.

Bests regards,


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## danbi (Jan 12, 2011)

There is higher chance for data corruption with UFS, than there is with ZFS. If you are not going to keep backups of your data, you will be better with raidz2, having total of 4TB storage but any two of the disks can fail at the same time.


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