FreeBSD as Server

[Eric Anderson]

Christian Damm wrote:
>
> hi all!
>
> Eric Anderson schrieb:
>> Patrik Forsberg wrote:
>>>> I am ISP admin. All my server work under Linux, but I want to try 
>>>> for this function FreeBSD. Once I used server under FreeBSD 5.3. 
>>>> Now I testing FreeBSD 6.0.
>>>> I liked functions such as dummy net, simple configuring, etc. But 
>>>> in FreeBSD I don't have alternative FileSystems exclude UFS and 
>>>> UFS2. On high-loaded FileServer is good idea to use XFS or 
>>>> ReiserFS, but this FS don't supported as well as in Linux. How I 
>>>> can to solve this problem?
>>>>     
>>>
>>> UFS2 scales very well on a havy loaded server so I see no reason to use
>>> RaiserFS or any other FS in FreeBSD ?
>>>   
>>
>> One good reason, would be journaling, but that isn't necessarily 
>> compelling.
>>
>>> I've ran, and is about to do so, a major newfeed machine, which use 
>>> alot
>>> of disk i/o, on UFS2 without any trouble.
>>> With softupdate in UFS2 the fsck in case of a crash is very time
>>> limited.
>>>   
>>
>> I don't believe softupdates changes the recovery time any significant 
>> amount, but it does ensure meta-data consistency.  With background 
>> fsck, your startup time can be reduced, which is very nice.
>>
>>> As for XFS and ReiserFS support you do have the support in ports:
>>>
>>> Path:   /usr/ports/sysutils/progsreiserfs
>>> Info:   Utilities and library to manipulate ReiserFS partitions
>>>
>>> Path:   /usr/ports/sysutils/xfsprogs
>>> Info:   A set of utilities and library to manipulate an xfs filesystem
>>
>> Note that those are read-only support.
>>
>> I have many FreeBSD servers here, that are *VERY HEAVILY* used, and 
>> the entire company depends on them.  I have 100's of GB's to tens of 
>> TB's hosted on FreeBSD servers, and I'm very happy to say it performs 
>> incredibly well, and is very stable.  Both 5.4(STABLE) and 6-STABLE 
>> are very solid for serving.
>>
>> One thing to be warned about - the larger the single filesystem, the 
>> more memory you will need for fsck's.  Actually, it's more dependant 
>> on number of files, but the relationship is there.  Full 2Tb 
>> filesystems (for me) require about 2.5GB of memory available for fsck 
>> use, YMMV.
>
> i too have some machines with large file systems (around 2TB (some of 
> them "only" have 512mb ram)) an never had any memory related fsck 
> issues in years now...just curious, but what could (should?) happen 
> without enough memory available during fsck?! slower fsck?

Like I mentioned before, it mostly depends on the number of files you 
have on the filesystem (inodes in use).  Having a 2Tb filesystem with a 
single 2Tb file won't take much more memory than an empty 2Tb 
filesystem, whereas a 2tb filesystem that is only 10% full, but has tens 
of millions of inodes in use will take significantly more memory. 

If fsck can't alloc enough memory to fit the entire inode info in 
memory, it fails to complete the fsck, leaving you with a dirty 
filesystem that can't be cleaned.

Eric




-- 
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Eric Anderson        Sr. Systems Administrator        Centaur Technology
Anything that works is better than anything that doesn't.
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