On Sun, May 22, 2011 at 2:06 PM, Keith Roberts keith@karsites.net wrote:
On Sun, 22 May 2011, yonatan pingle wrote:
To: CentOS mailing list centos@centos.org From: yonatan pingle yonatan.pingle@gmail.com Subject: Re: [CentOS] SSD for Centos SWAP /tmp & /var/ partition
On Sun, May 22, 2011 at 10:57 AM, Steven Crothers steven.crothers@gmail.com wrote:
I was running on 3gbps sata bus, and the performance was great, it just dies in one big crash without giving any clues about it.
If only SSD's were a viable solution for long-term storage, we could theoretically increase our virtualization many times over. It's to bad the technology hasn't come far enough to be used that way though without costing an arm and leg.
But it's going in the right direction now.
-- Steven Crothers steven.crothers@gmail.com
the only way to go with SSD is RAID due to these reasons. it's unlikely that two disks will die at the same time, so it's possible to use and enjoy them , but don't forget to have a fresh backup and a raid array. ( that should be done also with an ordinary disk array anyways ).
That's EXACTLY what I was thinking. Two 40GB SSD drives in a RAID array would not cost much at all. Move all the disk intensive stuff to that. I only have two root partitions of 20GB each for my main install - everything else is on other partitions on 2 x 500GB E-IDE drives. So putting the root partion on a small SSD (possibly RAIDed) is another option. Like most new electronics components, as time passes the mass production cost fall dramatically, and the technology improves. Look at the way HDD technology continues to advance.
Maybe in 5 years time the cost of SSD's will be alot cheaper? Possibly in another 15 years time HDD's with moving parts will be consigned to history and science museums? I'm watching this technology very closely, and I'm very tempted to buy a small 40GB SSD like OWC's.
They keep performing at optimal speed according to the specs for that drive.
The OWC SSD's are supposed to have a MTTF of 2 million hours, PLUS they do not degrade over time. So if an OWC keeps going until MTTF, that's 24 x 365 = 8760 HPY. 2000000 / 8760 = 228.31 years MTTF ?
So why does it only have a 3 year warranty? - LOL
For me anything on SWAP has to be better than a s/h drive thats had almost a years running time according to the SMART data on the drive:
9 Power_On_Hours 0x0032 090 090 000 Old_age Always - 7913
329 days running time already - let's see how long this one lasts before it kicks the bucket.
Kind Regards,
Keith Roberts
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I hardly swap to disk these days , and after the bad experience with ssd as swap only ... i would stick to RAM & sata.
RAM is so cheap , just get extra ram , and use PAE if 32bit (?) adjust vm.swappiness ( sysctl ) to a lower value then 60 ( default ) , and you will be fine swapping on sata drives if and when needed.
if you are afraid of memory fragmentation , don't be .. in most cases you will be rebooting the server when a new kernel update will come out as it is.... the main question is , which kind of applications are you planning to run on your machine, and what is your actual hardware *needs*, that only you can tell.
also, for /tmp , you might like the idea of a ramdisk ( or tmpfs ) , it is a great way to speed up things without breaking the piggy bank.
this is what i use in /etc/fstab for my home desktop as /tmp :
/tmpfs /tmp tmpfs size=512M,nr_inodes=5k,noatime,nodiratime,noexec 0 0
does the job well.
anyways - if it's for home usage Don't think twice get an SSD .