[Lustre-discuss] Solid State MDT

[Sarp Oral (oad)]

We have played around with that idea in one way or the other for a few times
in the past. It didn¹t seem to be cost effective.

We tried a RamSan device (300, if I am not mistaken) as a MDT, almost two
years ago. We compared the metadata rates of that with the ones we get from
our MDT on a DDN 9500 with write back cache on. DDN (simply a big cache with
a RAID 5 magnetic disk set behind it) turned out to be a more cost effective
solution for our installation and use cases.


We haven¹t evaluated any SSDs as a MDT since then as far as I can remember.


Sarp


On 4/9/09 6:07 PM, "Jordan Mendler" <jmendler at ucla.edu> wrote:

> Has anyone done any testing of modern SSD drives as an MDT for Lustre 1.6?
> Searching through the archives it seems that most of the posts related to SSD
> are either incomplete or slightly dated.
> 
> Does anyone have any input as to how they would compare to 15k RPM drives and
> at what deployment size the metadata performance gain would become noticeable?
> We are currently using Lustre as a small scratch space, and initially deployed
> our MDT as a 4x7200 RPM SATA RAID10 internal to the MDS. Metadata slow downs
> have become apparent during heavy use and/or small file operations, so we are
> currently deliberating which upgrade path to take.
> 
> As of now, our deployment is pretty small:
> 4 OSS's each with a 4x1TB RAID10 OST on disks internal to the OSS. Will
> increase the number of these as the system grows.
> ~50 clients that read/write large files that are striped across all OSS's.
> Will grow 2-4x in the next several months.
> We are currently on GigE, but will be switching to DDR-4x IB very soon.
> 
> Thanks,
> Jordan
> 
> 
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