Status of SSDs under Fedora ?

Andrew Haley aph at redhat.com
Fri Jun 11 09:13:16 UTC 2010


On 06/10/2010 11:19 PM, Phil Meyer wrote:
> On 06/10/2010 03:56 PM, Linuxguy123 wrote:
>> On Thu, 2010-06-10 at 14:50 -0700, Konstantin Svist wrote:
>>    
>>> On 06/10/2010 01:53 PM, Linuxguy123 wrote:
>>>      
>>>> I'm thinking of getting an Intel 160 GB SSD.   How would it work under
>>>> Linux ?
>>>>
>>>> I'm using ext4 for that drive right now.  Is there a better filesystem
>>>> for SSDs ?
>>>>
>>>> Is there anything that I should be aware of as far as switching ?
>>>>
>>>>        
>> Have you run an SSD ?  Is longevity really an issue or is it folklore ?
>>
>> Thanks
>>
>>    
> 
> It is bot real and folklore! :)
> 
> The fact is that any SSD, or other NAND type device has a limited number 
> of writes per address.  The real question is:
> 
> "With your data needs and patterns, will you actually need to write to 
> the same address over 100,000 times?"
> 
> For most people, that is a big fat NO.  The drives are smart enough to 
> re-arrange data around failed memory addresses.  So what happens most 
> often is a very slight decrease in available space over time.
> 
> The advice given is just smart, because most file systems will update 
> the same physical disk 'block' containing inode data whenever a file is 
> accessed (atime).  The chances of that update hitting the exact address 
> every time is quite high.
> 
> So, theoretically, if you just read a file on an SSD 100,000 times you 
> could destroy a single address location on the SSD. 

No, because all the SSDs you can buy today do some kind of wear levelling.

Andrew.


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