> From: zfs-discuss-boun...@opensolaris.org [mailto:zfs-discuss- > boun...@opensolaris.org] On Behalf Of Andrew Gabriel > > If you are reading blocks from your initial hdd images (golden images) > frequently enough, and you have enough memory on your system, these > blocks will end up on the ARC (memory) anyway. If you don't have enough > RAM for this to help, then you could add more memory, and/or an SSD as > a > L2ARC device ("cache" device in zpool command line terms).
Andrew's right. If you've got enough RAM in the system for a ramdisk to contain the whole image, then the kernel will automatically use that RAM for ARC cache anyway, so there should be no need for the ramdisk. The first time a block is read from the disk, it will be subsequently read from ram. If there's enough activity on all the clone disks to push the original disk out of ARC ram cache, that means the clones are benefitting more, and the original disk is benefitting less. You should let that happen, and optionally add more ram. But one more thing: If I'm not mistaken, L2ARC cached blocks will not get striped across more than one device in your L2ARC, which means your L2ARC only helps for latency, and not throughput. (I'm really not certain about this, but I think so.) Given the stated usage scenario, I'm not sure if latency or throughput would be more vital. _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
