# Recommendations for a FreeBSD server on DELL R515



## sovking (Apr 23, 2011)

Hello All,

I am planning a new server.

The *main functions* of this server will be:

 Email
 personal web pages
 file server (through sftp/samba)
 svn repository


The *secondary functions* will be:

 backup of personal user data (from desktop PC)
 store VM images


The *amount of users* that will access this server will be: *100 - 150*.

The hardware choosen is *DELL R515* with:

 2 x AMD Opteron 4184 2.8 Ghz
 16 GiB RAM DDR3 1333 Mhz (4x4 GiB sticks)
 Redundant PSU
 Controller PERC H200 flashed in IT mode (mps(4) driver)
 6 x 2TB Seagate Nearline SAS 7.2K rpm (for data)
 1 x Vertex 3 SSD 240 GB (for ZFS cache)
 1 x Intel SSD 32 GB with SLC memory (for ZIL)
 2 x 8GB USB keys (for O.S.: FreeBSD-8 Stable, mirrored)

The filesystem layout could be:

 the base system / and /usr on the read-only, mirrored USB sticks.
  The mirror is done by using gmirror and UFS
/usr/local, /usr/ports, /usr/obj, /var on ZFS pool
 /home and other storage-like folders on ZFS pool
 /tmp in swap-memory

The ZFS storage pool will be put on 6 x 2 TB NL SAS disk using RAIDZ2.
So the available space will be roughly: 4 x 2 = 8 TB.

Notes: 

 _I want have the base system on UFS on a separate disk for manageability reasons (updates, upgrades, etc.)._
 _I already own the 32 GiB SSD SLC disk, so I can reuse it, while the rest of the hardware is to be bought._
 
Here I write down some doubts I have about this configuration:

 16 GiB of RAM will be enough to manage the proposed functions, users, and storage space ?
 240 GB of ZFS cache on SSD will be in the right ratio with the 16 GiB of RAM memory and the 8 TB of storage size ? 
 32 GB of ZIL on a single SSD SLC is ok ? Or you recomend to mirror it on a slice of the Vertex 3 ? 
 Given the recomandation of setting the size the ZIL equal to 1/2 of RAM, 8 GB should be enough, right ?
 In this case, is better to move the OS on the SSD SLC disk (making a mirror with the VERTEX 3 ?) ?
        4.a.1 In this case is a problem (for the ZIL) making a mirror of different type of devices ?
 With regards of the requested functions, there is any performance hit having OS on memory sticks instead of SSD ?
 From a reability standpoint, is better to have the O.S. on memory sticks or on SSDs ?

 It could be better to not use the 32 GB SSD SLC, and but 2 x 120 GB vertex 2 to put in raid0 for ZFS cache and raid1 for ZFS ZIL ?
 Using ZFS Cache and ZFS Zil on the same device can produce a performance hit ?

 Intel 320 SSD has capacitors which could be more suitable for ZIL.
 It could be better to use this instead SSD SLC ? Or
 Do you reccomend a couple of this (without buying VERTEX 3) ?

 /tmp in swap-memory is compatible with using ZFS ?
I would be very grateful if I could have some recommendations/suggestions/corrections.
Feel free to recommend other hardware parts or different layout configurations (especially if the system cost will not change so much ).

Thanks in advance to everyone.


----------

