Store files in mongodb with Nodejs

I was saving my files on the FS of my server and now I want to save them in the mongodb.(for easier backup and stuff).I want to store files like 4-5Mb maximum and I tried save them with mongoose with Buffer type.I successfully saved them and retrieved them but I noticed a significant slow performance when i save and retrieve files like 4 or 5Mb.

My schema:

let fileSchema = new Schema({
name: {type: String, required: true},
_announcement: {type: Schema.Types.ObjectId, ref: 'Announcements'},
data: Buffer,
contentType: String
});

How I retrieve them from the expressjs server:

 let name = encodeURIComponent(file.name);
 res.writeHead(200, {
     'Content-Type': file.contentType,
     'Content-Disposition': 'attachment;filename*=UTF-8\'\'' + name
 });
 res.write(new Buffer(file.data));

My question is should I use some zlib compress functions like 'deflate' to compress buffer before saving them in the mongodb and then uncompress the binary before sending them to the client? Would this make the whole proccess faster?Am I missing something?

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