Search found 4 matches

by phat
Thu Aug 06, 2020 6:37 am
Forum: Technical Support
Topic: Deferred writes, urgent writes, SMR drives, and crash recovery
Replies: 3
Views: 190

Re: Deferred writes, urgent writes, SMR drives, and crash recovery

Thanks for the answers so far. Can you elaborate on the flush policy for urgent writes? Does PrimoCache try to flush blocks in sequential order, in as large batches as possible, during an urgent write? If it flushes blocks at random, it can greatly reduce the throughput of the SMR destination drive,...
by phat
Fri Jul 31, 2020 5:01 am
Forum: Technical Support
Topic: Does having more Ram for l1 cache and nvme size help l2
Replies: 2
Views: 175

Re: Does having more Ram for l1 cache and nvme size help l2

Windows does some RAM caching already, so you'll gain most with L2 SSD caching. Windows RAM caching seems to be dynamic, allowing apps to take over all of RAM if they need to, while I think PrimoCache reserves a fixed portion of your RAM for caching. I personally have disabled L1 caching in PrimoCac...
by phat
Fri Jul 31, 2020 3:29 am
Forum: Technical Support
Topic: Deferred writes, urgent writes, SMR drives, and crash recovery
Replies: 3
Views: 190

Deferred writes, urgent writes, SMR drives, and crash recovery

I want to put an SSD cache in front of some SMR (shingled) hard drives. Shingled drives are very slow handling random writes, and are fastest doing large sequential writes. I believe they are fastest when the writes sequentially fill up shingled zones, which I think are 256MB in size. When PrimoCach...
by phat
Tue Jul 14, 2020 12:55 am
Forum: Technical Support
Topic: Risk of Data Loss with Defer-Write on SSD cache?
Replies: 6
Views: 1144

Re: Risk of Data Loss with Defer-Write on SSD cache?

I love the performance boost from deferred writes, but am also worried about the risk of data loss. A UPS can protect from power outages, but nothing can protect from the occasional crash (and crashes are more often than power outages in my area, anyway). So, is it the case that if PrimoCache isn't ...