Nenhum_de_Nos wrote:
On Wed, Apr 9, 2008 at 9:47 AM, Arnaud Houdelette
<[EMAIL PROTECTED]> wrote:
Lev Serebryakov a écrit :



Hello, freebsd-stable.

 Does somebody use some software RAID5 on FreeBSD in real production
 system?

 I want to build storage server for my home: RAW photos, multi-layer
PhotoShop files and FLAC-encoded music consume a lot of space, and
they should be availible both from desktop & notebook.

 Also, all photo-content is unique, so I need some insuranse from
single HDD crash. I understand, that I will not safe from fire, PSU
failure and thing slike this.

 I selected hardware platform: Intel Q35-based MoBo with 6xSATA-II ports
(all of them is chipset-based, so no SiliconImage/JMicron/Whatever
crappy controllers), some low-end Core2Duo, 2Gb of memory.
 Storage will be 5x500Gb WD HDDs for RAID + one small HDD for boot,
system,
swap, etc. I want to have 2Tb (ok, not real Tb, I know) of "protected"
storage.
 I want to have maximum speed via 1Gb network, because graphic files
are big and should open fast. Not as fast as local ones, I understand
that, but speeds about 12-15Mb/s is not enough for sure :)

 Only problem I see: which software RAID5 solution should I prefer?
FreeBSD-based, of course!

 I see these variants:

 (1) FreeBSD 6(7?) + graid3. Slow, one disk for checksums is bottleneck,
    as far as I understand.

 (2) FreeBSD 6(7?) + gvinum/radi5. Is it stable enough?! Is it complete?
    when I try it about 6 months ago in VMWare installation with 5
    virtual disks, I got panics and strange behaviour after "crashing"
    one of virtual disks.

 (3) FreeBSD 6(7?) + graid5. Again, is it stable enough? There are
    THREE versions of it. Which one should I prefer? There was long
    thread about it some times ago without any clear conclusion. Does
    something changed?

 (4) FreeBSD 7 + ZFS "zraid". And again: stability. Too many messages
    about locks, crashes, etc. Code is experemental. Is it only for
    32 bit systems?

 (5) Do I miss something?

 (6) Solaris + ZFS? I don't want it, I know a little about Solaris
    administaration, and I already have FreeBSD servers and routers.

 I know, that 3ware or Areca controllers are very good. I know, that
 "gmirror" is very stable. But these variants are too expensive for
 home server :(

 Does somebody use some software RAID5 on FreeBSD in real production?
 Any advices?


 Hi !

 I personally use the 3 option for my personal Home File Server. I got
approximatly the same usage for the file server (mostly video, music,
photo). I built my own about 12 month ago.
 I reviewed the about the same variants as the one you propose :
 (1) Discarded for performance issues. Raid3 is slow. Really.
 (2) raid5/vinum is also slow. And as I understood at that time,  recovery
from lost hard drive wasn't easy enough for the freebsd niubee I was  then.
 (4) ZFS wasn't there yet. But I did test it on a test VMWare, and wasn't
convinced (mostly stability and memory issues).

 So I use geom_raid5. I sticked to the main distributions, which seemed more
stable at the moment. The kernel module is fairly simple to build/install.
Performance is (very) good for a software raid.
 I successfully switched the raid array from an i386 6.2-RELEASE to an an
amd64 7.0-RELEASE (with motherboard and CPU change) without any assle.

 For the moment, I use one big UFS+SU (and snapshots) on the whole array. I
successfuly tried unpplugging then replugging on of the drives, suddent
power loss, using the array with a missing disk (degraded mode). All did
work fine. (still, I use an UPS on the file server).

 The sole issue I had is with ataidle. I had to patch ata-disc.c to increase
the IO timeout. Without, the raid5 module detected temporary disk loss and
constantly launched rebuilds of the array.

 With 7.0, I wondered if I should use gjournal, but I'm not sure if it's
really the way to go on a file system dedicated to store many big files. So
I stick to soft updates.

 Current configuration is :
 / on a 2GB usb key
 /tmp on memory
 ports and source trees (and some portsnap stuff) on a small disk
 4x250 GB sata for the raid5 array.
 AMD A64 3200+ and 512 GB DDRII
 Realtek Gigabit nics.

 Copy from raid5 to /dev/null gives about 100MB/s
 Copy from /dev/random to raid5 about 40MB/s

 I use samba shares. I get about 40MB/s in both ways from another computer
on the network (enabling jumbo-frames gives a big boost).

 Hope my own story can help you in any way.

 Regards,

 Arnaud Houdelette

I know its been quite some time from the mail, but if you could say
where to find this module. eikipedia says its on freebsd 7 but there
is not this module for me (/boot/kernel/ there is no raid5 file).
everytime I search the internet I find old stuff about it.

If you could point me the site/article/anything :)

thanks,

matheus
Geom_raid5 is (unfortunatly ?) not part of Freebsd base.
You'll have to download and install the module and utility binaries and follow the (simple) instructions from this website :
http://home.tiscali.de/cmdr_faako/graid5-howto.html

In the meantime, somebody convinced me to give zfs a try, I backed up my data, converted the raid array to raidz pool and I must say I'm not disappointed.
+ Read performance (~160 Mo/s)
+ Instant snapshots
+ zfs filesystems goodness
+ better support from the community
- Stability issues : zfs and kernel need to be tuned
- Drive crash scenario may be a bit more complex


Regards,

Arnaud
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