I have a few questions about RAID 5, BBWC (Battery Backed Write Cache), filesystem (ext3) and optionally mysql.
I have a hypothesis and I ask Server Fault community to validate or not this one:
-The system is UP, applications works with database and use transactions
-The RAID system is configured with RAID5,write caching and battery (BBWC)
With this solution, when OS receive write ACK, data ar
I brought a HP Smart Array P410 controller and it is installed and working fine in a HP Prolient Microserver with 4 drives in two RAID 1 arrays.
I didn’t realise however that it came without any cache so would only work by directly writing straight to the disk, and the performance was horrible.
I have just provisioned a dedicated server on singlehop.
I'm running it through some tests to know what to expect performance-wise.
I have an Adaptec 3805 RAID controller and with two arrays without write cache. Now that I have bought the battery module for this controller, can I now enable the write cache on the existing arrays? Or do I need to delete and re-create new arrays with write cache on?
I have a 1tb array set up in raid 1 using mdadm on Ubuntu 8, to store mission-critical files. I'd like to speed up read/write, especially for large files by caching to an SSD. Is this possible? Does mdadm contain a facility to cache to another drive?
Alternatively, is there something I should do to assign ordinary RAM to caching?
The battery back-up (BBU) model:
admin enables write-back cache with BBU
writes are cached to the RAID controller's RAM (major performance benefit)
the battery saves uncommitted and cached data in the event of a power loss (reliability)
If I lose power and come back within a day or so, my data should be both complete and uncorrupted.
The downside to this is that, if the battery is dead or low
Hi all,
Code:
free -m
total used free shared buffers cached
I've been reading lately about write caching, NCQ, firmware bugs, barriers, etc regarding SATA drives, and I'm not sure what's the best setting that would make my data safe in case of a power failure.
From what I understand, NCQ allows the drive to reorder the writes to optimize performance, while keeping the kernel informed on which requests have been physically written.
Write cache makes the d
My programs use usual file system to do caching.
The amount of disk read and write is so phenomenal that I got to use SSD
But SSD don't have many spaces.
I wonder if PhP has a a caching mechanism that say cache data in memory and write only ocassionally?
I think I read that somewhere but then couldn't find it.
I checked memcached
Actually it doesn't.
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