[Info-vax] Databases versus RMS

[Johnny Billquist]

On 2012-04-20 17:44, Ken Fairfield wrote:
> On Thursday, April 19, 2012 11:18:01 PM UTC-7, Jan-Erik Soderholm wrote:
> [...]
>
>> The DECs SSD in SSB's (StorageWorks disks) was RAM based as far as I know.
>> That is, did not retain data at power loss. Was often used as one part
>> of a schadow-set so that all reads was doen from the RAM disks and all
>> writes went to both (and thus stored permanently).
>
> The first Intel fab I worked at was using DEC SSD's for the "hot"
> database files.  This was VAXcluster (7800's IIRC).  I'm pretty
> sure the SSD's were in SSB's.  I *know* that these SSD's had
> rotating disks in the same package (SSB) for non-volatile storage.
> I don't recall for sure, but I *think* they had (small?) batteries
> as well so the memory could be written to the disks in the event of
> a power failure.
>
> What I found interesting is that, by the time I got there, these
> SSD's were suffering a fairly high failure rate.  And it was
> universally the rotating disks that were failing. ;-p  OTOH, by
> the time they were failing, you couldn't buy such things anymore
> (from DEC/Compaq).
>
> We were able to get as good performance for the database over FC/HSG
> with Host-Based RAID striping (and a few other configuration tricks)
> on the Alphas that replaced the VAXes, so we didn't need SSD's anymore.

Time to get the terminology right here. What you are talking about is 
SBB, not SSB. :-)

(StorageWorks Building Blocks)

	Johnny

-- 
Johnny Billquist                  || "I'm on a bus
                                   ||  on a psychedelic trip
email: bqt at softjar.se             ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol