[ltp] Slightly OT: Filesystem performance on SSD vs HDD: test data request

[Volker Krueger]

Hi Theo,

FYI:

hdparm -t gives me on my X25 SSD, 128Gig a rate of  219.30 MB/sec.
I did not do any tuning of the SSD.
I am surprised that your value is so much lower.

cheers,
Volker





Theodore Tso wrote:
> On Mon, Aug 17, 2009 at 08:22:42PM +0100, Richard Neill wrote:
>   
>> Dear All,
>>
>> I've been looking into filesystem performance for postgresql on various  
>> configurations. I've found out quite a lot. I'm still curious about how  
>> it works on a really good SSD; does anyone have an Intel X-25 that they  
>> would be willing to run a simple test with?
>>     
>
> I did the test on a T400 (Core 2.53 GHz), using LVM and mke2fs
> parameters of "mke2fs -b 4096 -t ext[234] /dev/<PV>/test 131072".
> This means that I was using a half gigabyte test partition, freshly
> created, on an otherwise idle system.  (If you have any other I/O
> writing to the same disk, or especially the same filesystem,
> fdatasync's performance numbers will be very, very different.)  I am
> running a 2.6.31-rc5 kernel.
>
> On the 5400rpm HDD in the Ultrabay slot:
>
> hdparm -t	66 MB/sec
> ext2		1.4s
> ext3		2.2s
> ext4/barrier=0	2.2s
> ext4/barrier=1	29.3s
>
> On the Intel X25-M 80GB SSD as the primary disk:
>
> hdparm -t	157 MB/sec
> ext2		0.23s
> ext3		0.46s
> ext4/barrier=0	0.46s
> ext4/barrier=1	2.90s
>
> Note that ext2/ext3 defaults to barrier=0, while ext4 uses barrier=1
> as the default.  So I did the test both ways in order to have a fair
> apples-to-apples comparison.
>
> 						- Ted
>