hi all,
maybe to clarify a bit, e.g.
https://indico.cern.ch/event/755842/contributions/3243386/attachments/1784159/2904041/2019-jcollet-openlab.pdf
clearly shows that the db+wal disks are not saturated,
but we are wondering what is really needed/acceptable wrt throughput and
latency (eg is a 6gbps sata enough or is 12gbps sas needed); we are
thinking combining 4 or 5 7.2k rpms disks with one ssd.
similar question with the read-intensive: how much is actually written
to the db+wal compared to the data disk? is that 1-to-1?
do people see eg 1 DWPD on their db+wal devices? (i guess it depends;)
if so, what kind of workload daily averages are this in terms of volume?
thanks for pointing out the capacitor isue, something to defintely
double check for the (cheaper) read intensive ssd.
stijn
On 10/4/19 7:29 PM, Vitaliy Filippov wrote:
> WAL/DB isn't "read intensive". It's more "write intensive" :) use server
> SSDs with capacitors to get adequate write performance.
>
>> Hi all,
>>
>> We are thinking about putting our wal/db of hdds/ on ssds. If we would
>> put the wal&db of 4 HDDS on 1 SSD as recommended, what type of SSD would
>> suffice?
>> We were thinking of using SATA Read Intensive 6Gbps 1DWPD SSDs.
>>
>> Does someone has some experience with this configuration? Would we need
>> SAS ssds instead of SATA? And Mixed Use 3WPD instead of Read intensive?
>
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