[Info-vax] Databases versus RMS

[glen herrmannsfeldt]

abrsvc <dansabrservices at yahoo.com> wrote:
> On Friday, April 20, 2012 11:44:36 AM UTC-4, Ken Fairfield wrote:

(snip)
>> 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).

(snip)
> The disks were there for backing up the memory in the event of 
> a power failure.  There was at least one attempt to have the 
> drives in "standby" or not spinning, but the spinup time was 
> too long for reliable backups.  Thus, the mode was to keep the 
> drives spinning and ready for data transfer.  

I wonder if just spinning, and rarely seeking, is not so good
for the drives. The actuator might take a set in one position,
and then not move when it needs to.

-- glen