Advice for the serveur usage - L2 cache for write
Posted: Fri Dec 30, 2011 8:15 am
In the serveur usage, we don't care about the SSD disk life cycle at all, however, the IOPS is the key parameter for the enduser. And for the raid 5 or raid 10, write IOPS is reduced by 2 - 4 or more.
So it will be very important that: in the L2 cache for the write usage:
1. The data could be deferred write 10s by memory and then writen to SSD
2. the data in SSD will be writen to HDD for a longer defer duraion. However, even the power is down for the duration. We can garantee that no data will be lost.
In fact, in the real case, memory defer write will probably be rejeted because it will cause the data lost and no data lost will be permitted. L2 ssd cache for write activities is more important. (Because no data will be lost)
So it will be very important that: in the L2 cache for the write usage:
1. The data could be deferred write 10s by memory and then writen to SSD
2. the data in SSD will be writen to HDD for a longer defer duraion. However, even the power is down for the duration. We can garantee that no data will be lost.
In fact, in the real case, memory defer write will probably be rejeted because it will cause the data lost and no data lost will be permitted. L2 ssd cache for write activities is more important. (Because no data will be lost)